The remote Redhat Enterprise Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2021:0155 advisory.

    The dnsmasq packages contain Dnsmasq, a lightweight DNS (Domain Name Server) forwarder and DHCP (Dynamic     Host Configuration Protocol) server.

    Security Fix(es):

    * dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path attacker     (CVE-2020-25684)

    * dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker     (CVE-2020-25685)

    * dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path     attacker (CVE-2020-25686)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

An update of the dnsmasq package has been released.

According to the versions of the dnsmasq package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - A flaw was found in dnsmasq before version 2.83. A     heap-based buffer overflow was discovered in the way     RRSets are sorted before validating with DNSSEC data.
    An attacker on the network, who can forge DNS replies     such as that they are accepted as valid, could use this     flaw to cause a buffer overflow with arbitrary data in     a heap memory segment, possibly executing code on the     machine. The highest threat from this vulnerability is     to data confidentiality and integrity as well as system     availability.(CVE-2020-25681)

  - A flaw was found in dnsmasq before 2.83. A buffer     overflow vulnerability was discovered in the way     dnsmasq extract names from DNS packets before     validating them with DNSSEC data. An attacker on the     network, who can create valid DNS replies, could use     this flaw to cause an overflow with arbitrary data in a     heap-allocated memory, possibly executing code on the     machine. The flaw is in the rfc1035.c:extract_name()     function, which writes data to the memory pointed by     name assuming MAXDNAME*2 bytes are available in the     buffer. However, in some code execution paths, it is     possible extract_name() gets passed an offset from the     base buffer, thus reducing, in practice, the number of     available bytes that can be written in the buffer. The     highest threat from this vulnerability is to data     confidentiality and integrity as well as system     availability.(CVE-2020-25682)

  - A flaw was found in dnsmasq before version 2.83. A     heap-based buffer overflow was discovered in dnsmasq     when DNSSEC is enabled and before it validates the     received DNS entries. A remote attacker, who can create     valid DNS replies, could use this flaw to cause an     overflow in a heap-allocated memory. This flaw is     caused by the lack of length checks in     rfc1035.c:extract_name(), which could be abused to make     the code execute memcpy() with a negative size in     get_rdata() and cause a crash in dnsmasq, resulting in     a denial of service. The highest threat from this     vulnerability is to system     availability.(CVE-2020-25683)

  - A flaw was found in dnsmasq before version 2.83. When     getting a reply from a forwarded query, dnsmasq checks     in the forward.c:reply_query() if the reply destination     address/port is used by the pending forwarded queries.
    However, it does not use the address/port to retrieve     the exact forwarded query, substantially reducing the     number of attempts an attacker on the network would     have to perform to forge a reply and get it accepted by     dnsmasq. This issue contrasts with RFC5452, which     specifies a query's attributes that all must be used to     match a reply. This flaw allows an attacker to perform     a DNS Cache Poisoning attack. If chained with     CVE-2020-25685 or CVE-2020-25686, the attack complexity     of a successful attack is reduced. The highest threat     from this vulnerability is to data     integrity.(CVE-2020-25684)

  - A flaw was found in dnsmasq before version 2.83. When     getting a reply from a forwarded query, dnsmasq checks     in forward.c:reply_query(), which is the forwarded     query that matches the reply, by only using a weak hash     of the query name. Due to the weak hash (CRC32 when     dnsmasq is compiled without DNSSEC, SHA-1 when it is)     this flaw allows an off-path attacker to find several     different domains all having the same hash,     substantially reducing the number of attempts they     would have to perform to forge a reply and get it     accepted by dnsmasq. This is in contrast with RFC5452,     which specifies that the query name is one of the     attributes of a query that must be used to match a     reply. This flaw could be abused to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25684 the     attack complexity of a successful attack is reduced.
    The highest threat from this vulnerability is to data     integrity.(CVE-2020-25685)

  - A flaw was found in dnsmasq before version 2.83. When     receiving a query, dnsmasq does not check for an     existing pending request for the same name and forwards     a new request. By default, a maximum of 150 pending     queries can be sent to upstream servers, so there can     be at most 150 queries for the same name. This flaw     allows an off-path attacker on the network to     substantially reduce the number of attempts that it     would have to perform to forge a reply and have it     accepted by dnsmasq. This issue is mentioned in the     'Birthday Attacks' section of RFC5452. If chained with     CVE-2020-25684, the attack complexity of a successful     attack is reduced. The highest threat from this     vulnerability is to data integrity.(CVE-2020-25686)

  - A flaw was found in dnsmasq before version 2.83. A     heap-based buffer overflow was discovered in dnsmasq     when DNSSEC is enabled and before it validates the     received DNS entries. This flaw allows a remote     attacker, who can create valid DNS replies, to cause an     overflow in a heap-allocated memory. This flaw is     caused by the lack of length checks in     rfc1035.c:extract_name(), which could be abused to make     the code execute memcpy() with a negative size in     sort_rrset() and cause a crash in dnsmasq, resulting in     a denial of service. The highest threat from this     vulnerability is to system     availability.(CVE-2020-25687)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Fedora 32 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-2e4c3d5a9d advisory.

  - A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way     RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS     replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with     arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from     this vulnerability is to data confidentiality and integrity as well as system availability.
    (CVE-2020-25681)

  - A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq     extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who     can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-     allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name()     function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the     buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from     the base buffer, thus reducing, in practice, the number of available bytes that can be written in the     buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as     system availability. (CVE-2020-25682)

  - A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq     when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create     valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is     caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code     execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial     of service. The highest threat from this vulnerability is to system availability. (CVE-2020-25683)

  - A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq     checks in the forward.c:reply_query() if the reply destination address/port is used by the pending     forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query,     substantially reducing the number of attempts an attacker on the network would have to perform to forge a     reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's     attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful     attack is reduced. The highest threat from this vulnerability is to data integrity. (CVE-2020-25684)

  - A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq     checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a     weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1     when it is) this flaw allows an off-path attacker to find several different domains all having the same     hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it     accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the     attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced.
    The highest threat from this vulnerability is to data integrity. (CVE-2020-25685)

  - A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an     existing pending request for the same name and forwards a new request. By default, a maximum of 150     pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name.
    This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that     it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the     Birthday Attacks section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a     successful attack is reduced. The highest threat from this vulnerability is to data integrity.
    (CVE-2020-25686)

  - A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq     when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote     attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is     caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code     execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial     of service. The highest threat from this vulnerability is to system availability. (CVE-2020-25687)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2021:0009 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2020-25681:
    A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way     RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS     replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with     arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from     this vulnerability is to data confidentiality and integrity as well as system availability.

    CVE-2020-25682:
    A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq     extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who     can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-     allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name()     function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the     buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from     the base buffer, thus reducing, in practice, the number of available bytes that can be written in the     buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as     system availability.

    CVE-2020-25683:
    A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq     when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create     valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is     caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code     execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial     of service. The highest threat from this vulnerability is to system availability.

    CVE-2020-25684:
    A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq     checks in the forward.c:reply_query() if the reply destination address/port is used by the pending     forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query,     substantially reducing the number of attempts an attacker on the network would have to perform to forge a     reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's     attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful     attack is reduced. The highest threat from this vulnerability is to data integrity.

    CVE-2020-25685:
    A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq     checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a     weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1     when it is) this flaw allows an off-path attacker to find several different domains all having the same     hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it     accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the     attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced.
    The highest threat from this vulnerability is to data integrity.

    CVE-2020-25686:
    A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an     existing pending request for the same name and forwards a new request. By default, a maximum of 150     pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name.
    This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that     it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the     Birthday Attacks section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a     successful attack is reduced. The highest threat from this vulnerability is to data integrity.

    CVE-2020-25687:
    A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq     when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote     attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is     caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code     execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial     of service. The highest threat from this vulnerability is to system availability.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2021-1363:03 advisory.

    * dnsmasq: heap-based buffer overflow in sort_rrset() when DNSSEC is enabled (CVE-2020-25681)
      * dnsmasq: buffer overflow in extract_name() due to missing length check when DNSSEC is enabled     (CVE-2020-25682)
      * dnsmasq: heap-based buffer overflow with large memcpy in get_rdata() when DNSSEC is enabled     (CVE-2020-25683)
      * dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path     attacker (CVE-2020-25684)
      * dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker     (CVE-2020-25685)
      * dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path     attacker (CVE-2020-25686)
      * dnsmasq: heap-based buffer overflow with large memcpy in sort_rrset() when DNSSEC is enabled     (CVE-2020-25687)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of AHV installed on the remote host is prior to 20201105.1045. It is, therefore, affected by multiple vulnerabilities as referenced in the NXSA-AHV-20201105.1045 advisory.

  - A heap-based buffer overflow was found in the way sudo parses command line arguments. This flaw is     exploitable by any local user who can execute the sudo command without authentication. Successful     exploitation of this flaw could lead to privilege escalation.  (CVE-2021-3156)

  - Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which     allows privilege escalation to root via sudoedit -s and a command-line argument that ends with a single     backslash character. (CVE-2021-3156)

  - Net-SNMP through 5.8 has Improper Privilege Management because SNMP WRITE access to the EXTEND MIB     provides the ability to run arbitrary commands as root. (CVE-2020-15862)

  - A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq     checks in the forward.c:reply_query() if the reply destination address/port is used by the pending     forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query,     substantially reducing the number of attempts an attacker on the network would have to perform to forge a     reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's     attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful     attack is reduced. The highest threat from this vulnerability is to data integrity. (CVE-2020-25684)

  - A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq     checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a     weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1     when it is) this flaw allows an off-path attacker to find several different domains all having the same     hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it     accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the     attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache     Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced.
    The highest threat from this vulnerability is to data integrity. (CVE-2020-25685)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 7 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2021:0395 advisory.

    The redhat-virtualization-host packages provide the Red Hat Virtualization Host. These packages include     redhat-release-virtualization-host. Red Hat Virtualization Hosts (RHVH) are installed using a special     build of Red Hat Enterprise Linux with only the packages required to host virtual machines. RHVH features     a Cockpit user interface for monitoring the host's resources and performing administrative tasks.

    Security Fix(es):

    * sudo: Heap buffer overflow in argument parsing (CVE-2021-3156)

    * dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path attacker     (CVE-2020-25684)

    * dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker     (CVE-2020-25685)

    * dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path     attacker (CVE-2020-25686)

    For more details about the security issue(s), including the impact, a CVSS score, and other related     information, refer to the CVE page(s) listed in the References section.

    Bug Fix(es):

    * When performing an upgrade of the Red Hat Virtualization Host using the command `yum update`, the yum     repository for RHV 4.3 EUS is unreachable

    As a workaround, run the following command:
    `# yum update --releasever=7Server` (BZ#1899378)

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	名称	产品	系列	发布时间	最近更新时间	严重程度
145085	RHEL 7 : dnsmasq (RHSA-2021:0155)	Nessus	Red Hat Local Security Checks	2021/1/19	2024/11/7	low
145420	Photon OS 1.0: Dnsmasq PHSA-2021-1.0-0356	Nessus	PhotonOS Local Security Checks	2021/1/26	2022/12/5	high
146224	EulerOS 2.0 SP9 : dnsmasq (EulerOS-SA-2021-1263)	Nessus	Huawei Local Security Checks	2021/2/5	2024/1/23	high
148783	Fedora 32 : dnsmasq (2021-2e4c3d5a9d)	Nessus	Fedora Local Security Checks	2021/4/19	2022/12/5	high
236546	Alibaba Cloud Linux 3 : 0009: dnsmasq (ALINUX3-SA-2021:0009)	Nessus	Alibaba Cloud Linux Local Security Checks	2025/5/14	2025/5/15	high
291655	MiracleLinux 8 : dnsmasq-2.79-13.el8.1 (AXSA:2021-1363:03)	Nessus	Miracle Linux Local Security Checks	2026/1/19	2026/1/20	high
164555	Nutanix AHV : Multiple Vulnerabilities (NXSA-AHV-20201105.1045)	Nessus	Misc.	2022/9/1	2025/2/19	medium
146093	RHEL 7 : RHV-H security, update (redhat-virtualization-host) 4.3.13 (Important) (RHSA-2021:0395)	Nessus	Red Hat Local Security Checks	2021/2/3	2026/4/30	high

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