Several vulnerabilities have been discovered in libVNC (libvncserver Debian package), an implemenantation of the VNC server and client protocol.

CVE-2019-20839

libvncclient/sockets.c in LibVNCServer had a buffer overflow via a long socket filename.

CVE-2020-14397

libvncserver/rfbregion.c had a NULL pointer dereference.

CVE-2020-14399

Byte-aligned data was accessed through uint32_t pointers in libvncclient/rfbproto.c.

CVE-2020-14400

Byte-aligned data was accessed through uint16_t pointers in libvncserver/translate.c.

CVE-2020-14401

libvncserver/scale.c had a pixel_value integer overflow.

CVE-2020-14402

libvncserver/corre.c allowed out-of-bounds access via encodings.

CVE-2020-14403

libvncserver/hextile.c allowed out-of-bounds access via encodings.

CVE-2020-14404

libvncserver/rre.c allowed out-of-bounds access via encodings.

CVE-2020-14405

libvncclient/rfbproto.c does not limit TextChat size.

For Debian 8 'Jessie', these problems have been fixed in version 0.9.9+dfsg2-6.1+deb8u8.

We recommend that you upgrade your libvncserver packages.

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

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4434-1 advisory.

    Ramin Farajpour Cami discovered that LibVNCServer incorrectly handled certain malformed unix socket names.
    A remote attacker could exploit this with a crafted socket name, leading to a denial of service, or     possibly execute arbitrary code. (CVE-2019-20839)

    It was discovered that LibVNCServer did not properly access byte-aligned data. A remote attacker could     possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. This issue only     affected Ubuntu 18.04 LTS and Ubuntu 16.04 LTS. (CVE-2019-20840)

    Christian Beier discovered that LibVNCServer incorrectly handled anonymous TLS connections. A remote     attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service.
    This issue only affected Ubuntu 20.04 LTS. (CVE-2020-14396)

    It was discovered that LibVNCServer incorrectly handled region clipping. A remote attacker could possibly     use this issue to cause LibVNCServer to crash, resulting in a denial of service. (CVE-2020-14397)

    It was discovered that LibVNCServer did not properly reset incorrectly terminated TCP connections. A     remote attacker could possibly use this issue to cause an infinite loop, resulting in a denial of service.
    (CVE-2020-14398)

    It was discovered that LibVNCServer did not properly access byte-aligned data. A remote attacker could     possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. (CVE-2020-14399,     CVE-2020-14400)

    It was discovered that LibVNCServer incorrectly handled screen scaling on the server side. A remote     attacker could use this issue to cause LibVNCServer to crash, resulting in a denial of service, or     possibly execute arbitrary code. (CVE-2020-14401)

    It was discovered that LibVNCServer incorrectly handled encodings. A remote attacker could use this issue     to cause LibVNCServer to crash, resulting in a denial of service, or possibly execute arbitrary code.
    (CVE-2020-14402, CVE-2020-14403, CVE-2020-14404)

    It was discovered that LibVNCServer incorrectly handled TextChat messages. A remote attacker could     possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. (CVE-2020-14405)

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

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

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

  - An issue was discovered in LibVNCServer before 0.9.13.
    There is an information leak (of uninitialized memory     contents) in the libvncclient/rfbproto.c     ConnectToRFBRepeater function.(CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13     has a buffer overflow via a long socket     filename.(CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/rfbregion.c has a NULL pointer     dereference.(CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13.
    An improperly closed TCP connection causes an infinite     loop in libvncclient/sockets.c.(CVE-2020-14398)

  - An issue was discovered in LibVNCServer before 0.9.13.
    Byte-aligned data is accessed through uint32_t pointers     in libvncclient/rfbproto.c.(CVE-2020-14399)

  - An issue was discovered in LibVNCServer before 0.9.13.
    Byte-aligned data is accessed through uint16_t pointers     in libvncserver/translate.c.(CVE-2020-14400)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/scale.c has a pixel_value integer     overflow.(CVE-2020-14401)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/corre.c allows out-of-bounds access via     encodings.(CVE-2020-14402)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/hextile.c allows out-of-bounds access via     encodings.(CVE-2020-14403)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/rre.c allows out-of-bounds access via     encodings.(CVE-2020-14404)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncclient/rfbproto.c does not limit TextChat     size.(CVE-2020-14405)

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.

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

  - LibVNCServer makes writing a VNC server (or more     correctly, a program exporting a frame-buffer via the     Remote Frame Buffer protocol) easy. It hides the     programmer from the tedious task of managing clients     and compression schemata.Security Fix(es):An issue was     discovered in LibVNCServer before 0.9.13. There is an     information leak (of uninitialized memory contents) in     the libvncclient/rfbproto.c ConnectToRFBRepeater     function.(CVE-2018-21247)libvncclient/sockets.c in     LibVNCServer before 0.9.13 has a buffer overflow via a     long socket filename.(CVE-2019-20839)An issue was     discovered in LibVNCServer before 0.9.13.
    libvncserver/rfbregion.c has a NULL pointer     dereference.(CVE-2020-14397)An issue was discovered in     LibVNCServer before 0.9.13. An improperly closed TCP     connection causes an infinite loop in     libvncclient/sockets.c.(CVE-2020-14398)An issue was     discovered in LibVNCServer before 0.9.13. Byte-aligned     data is accessed through uint32_t pointers in     libvncclient/rfbproto.c. NOTE: there is reportedly 'no     trust boundary crossed.'(CVE-2020-14399)An issue was     discovered in LibVNCServer before 0.9.13. Byte-aligned     data is accessed through uint16_t pointers in     libvncserver/translate.c. NOTE: Third parties do not     consider this to be a vulnerability as there is no     known path of exploitation or cross of a trust     boundary.(CVE-2020-14400)An issue was discovered in     LibVNCServer before 0.9.13. libvncserver/scale.c has a     pixel_value integer overflow.(CVE-2020-14401)An issue     was discovered in LibVNCServer before 0.9.13.
    libvncserver/corre.c allows out-of-bounds access via     encodings.(CVE-2020-14402)An issue was discovered in     LibVNCServer before 0.9.13. libvncserver/hextile.c     allows out-of-bounds access via     encodings.(CVE-2020-14403)An issue was discovered in     LibVNCServer before 0.9.13. libvncserver/rre.c allows     out-of-bounds access via encodings.(CVE-2020-14404)An     issue was discovered in LibVNCServer before 0.9.13.
    libvncclient/rfbproto.c does not limit TextChat     size.(CVE-2020-14405)libvncclient/cursor.c in     LibVNCServer through 0.9.12 has a HandleCursorShape     integer overflow and heap-based buffer overflow via a     large height or width value. (CVE-2019-20788)

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 Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2021-1811 advisory.

    - Fix CVE-2020-25708       Resolves: #1898078
    - Fix CVE-2019-20839       Resolves: #1851032
    - Fix CVE-2018-21247       Resolves: #1852516
    - Fix CVE-2020-14405       Resolves: #1860527

Tenable has extracted the preceding description block directly from the Oracle 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 SUSE Linux SLES11 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2020:14424-1 advisory.

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference. (CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13. An improperly closed TCP connection causes an     infinite loop in libvncclient/sockets.c. (CVE-2020-14398)

  - ** DISPUTED ** An issue was discovered in LibVNCServer before 0.9.13. Byte-aligned data is accessed     through uint32_t pointers in libvncclient/rfbproto.c. NOTE: there is reportedly no trust boundary     crossed. (CVE-2020-14399)

  - ** DISPUTED ** An issue was discovered in LibVNCServer before 0.9.13. Byte-aligned data is accessed     through uint16_t pointers in libvncserver/translate.c. NOTE: Third parties do not consider this to be a     vulnerability as there is no known path of exploitation or cross of a trust boundary. (CVE-2020-14400)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/scale.c has a pixel_value integer     overflow. (CVE-2020-14401)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/corre.c allows out-of-bounds access     via encodings. (CVE-2020-14402)

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

This update for LibVNCServer fixes the following issues :

security update

added patches fix CVE-2018-21247 [bsc#1173874], uninitialized memory contents are vulnerable to Information leak

  + LibVNCServer-CVE-2018-21247.patch fix CVE-2019-20839     [bsc#1173875], buffer overflow in     ConnectClientToUnixSock()

  + LibVNCServer-CVE-2019-20839.patch fix CVE-2019-20840     [bsc#1173876], unaligned accesses in hybiReadAndDecode     can lead to denial of service

  + LibVNCServer-CVE-2019-20840.patch fix CVE-2020-14398     [bsc#1173880], improperly closed TCP connection causes     an infinite loop in libvncclient/sockets.c

  + LibVNCServer-CVE-2020-14398.patch fix CVE-2020-14397     [bsc#1173700], NULL pointer dereference in     libvncserver/rfbregion.c

  + LibVNCServer-CVE-2020-14397.patch fix CVE-2020-14399     [bsc#1173743], Byte-aligned data is accessed through     uint32_t pointers in libvncclient/rfbproto.c.

  + LibVNCServer-CVE-2020-14399.patch fix CVE-2020-14400     [bsc#1173691], Byte-aligned data is accessed through     uint16_t pointers in libvncserver/translate.c.

  + LibVNCServer-CVE-2020-14400.patch fix CVE-2020-14401     [bsc#1173694], potential integer overflows in     libvncserver/scale.c

  + LibVNCServer-CVE-2020-14401.patch fix CVE-2020-14402     [bsc#1173701], out-of-bounds access via encodings.

  + LibVNCServer-CVE-2020-14402,14403,14404.patch fix     CVE-2017-18922 [bsc#1173477], preauth buffer overwrite

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

The remote CentOS Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the CESA-2021:1811 advisory.

  - libvncserver: uninitialized memory contents are vulnerable to Information Leak (CVE-2018-21247)

  - libvncserver: buffer overflow in ConnectClientToUnixSock() (CVE-2019-20839)

  - libvncserver: libvncserver/rfbregion.c has a NULL pointer dereference (CVE-2020-14397)

  - libvncserver: libvncclient/rfbproto.c does not limit TextChat size (CVE-2020-14405)

  - libvncserver: libvncserver/rfbserver.c has a divide by zero which could result in DoS (CVE-2020-25708)

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

This update for LibVNCServer fixes the following issues :

security update fix CVE-2018-21247 [bsc#1173874], uninitialized memory contents are vulnerable to Information leak fix CVE-2019-20839 [bsc#1173875], buffer overflow in ConnectClientToUnixSock() fix CVE-2019-20840 [bsc#1173876], unaligned accesses in hybiReadAndDecode can lead to denial of service fix CVE-2020-14398 [bsc#1173880], improperly closed TCP connection causes an infinite loop in libvncclient/sockets.c fix CVE-2020-14397 [bsc#1173700], NULL pointer dereference in libvncserver/rfbregion.c fix CVE-2020-14399 [bsc#1173743], Byte-aligned data is accessed through uint32_t pointers in libvncclient/rfbproto.c. fix CVE-2020-14400 [bsc#1173691], Byte-aligned data is accessed through uint16_t pointers in libvncserver/translate.c. fix CVE-2020-14401 [bsc#1173694], potential integer overflows in libvncserver/scale.c fix CVE-2020-14402 [bsc#1173701], out-of-bounds access via encodings. fix CVE-2020-14403 [bsc#1173701], out-of-bounds access via encodings. fix CVE-2020-14404 [bsc#1173701], out-of-bounds access via encodings. fix CVE-2017-18922 [bsc#1173477], preauth buffer overwrite

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

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4573-1 advisory.

    Nicolas Ruff discovered that Vino incorrectly handled large ClientCutText messages. A remote attacker     could use this issue to cause the server to crash, resulting in a denial of service. (CVE-2014-6053)

    It was discovered that Vino incorrectly handled certain packet lengths. A remote attacker could possibly     use this issue to obtain sensitive information, cause a denial of service, or execute arbitrary code.
    (CVE-2018-7225)

    Pavel Cheremushkin discovered that an information disclosure vulnerability existed in Vino when sending a     ServerCutText message. An attacker could possibly use this issue to expose sensitive information.
    (CVE-2019-15681)

    It was discovered that Vino incorrectly handled region clipping. A remote attacker could possibly use this     issue to cause Vino to crash, resulting in a denial of service. (CVE-2020-14397)

    It was discovered that Vino incorrectly handled encodings. A remote attacker could use this issue to cause     Vino to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-14402,     CVE-2020-14403, CVE-2020-14404)

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

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

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

  - An issue was discovered in LibVNCServer before 0.9.13.
    There is an information leak (of uninitialized memory     contents) in the libvncclient/rfbproto.c     ConnectToRFBRepeater function.(CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13     has a buffer overflow via a long socket     filename.(CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/rfbregion.c has a NULL pointer     dereference.(CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13.
    An improperly closed TCP connection causes an infinite     loop in libvncclient/sockets.c.(CVE-2020-14398)

  - An issue was discovered in LibVNCServer before 0.9.13.
    Byte-aligned data is accessed through uint32_t pointers     in libvncclient/rfbproto.c.(CVE-2020-14399)

  - An issue was discovered in LibVNCServer before 0.9.13.
    Byte-aligned data is accessed through uint16_t pointers     in libvncserver/translate.c.(CVE-2020-14400)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/scale.c has a pixel_value integer     overflow.(CVE-2020-14401)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/corre.c allows out-of-bounds access via     encodings.(CVE-2020-14402)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/hextile.c allows out-of-bounds access via     encodings.(CVE-2020-14403)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/rre.c allows out-of-bounds access via     encodings.(CVE-2020-14404)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncclient/rfbproto.c does not limit TextChat     size.(CVE-2020-14405)

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 AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2021:1811 advisory.

  - An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized     memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function. (CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.
    (CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference. (CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat     size. (CVE-2020-14405)

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

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

The remote Rocky Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2021:1811 advisory.

  - An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized     memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function. (CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.
    (CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference. (CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat     size. (CVE-2020-14405)

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

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
137907	Debian DLA-2264-1 : libvncserver security update	Nessus	Debian Local Security Checks	2020/7/1	2024/3/5	medium
138999	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : LibVNCServer vulnerabilities (USN-4434-1)	Nessus	Ubuntu Local Security Checks	2020/7/27	2025/9/3	medium
140161	EulerOS 2.0 SP5 : libvncserve (EulerOS-SA-2020-1940)	Nessus	Huawei Local Security Checks	2020/9/2	2022/5/12	high
140883	EulerOS 2.0 SP3 : libvncserver (EulerOS-SA-2020-2116)	Nessus	Huawei Local Security Checks	2020/9/28	2024/2/19	critical
149968	Oracle Linux 8 : libvncserver (ELSA-2021-1811)	Nessus	Oracle Linux Local Security Checks	2021/5/26	2024/10/22	high
150525	SUSE SLES11 Security Update : LibVNCServer (SUSE-SU-2020:14424-1)	Nessus	SuSE Local Security Checks	2021/6/10	2021/6/10	medium
138548	SUSE SLED15 / SLES15 Security Update : LibVNCServer (SUSE-SU-2020:1922-1)	Nessus	SuSE Local Security Checks	2020/7/16	2024/3/1	critical
149728	CentOS 8 : libvncserver (CESA-2021:1811)	Nessus	CentOS Local Security Checks	2021/5/19	2024/1/1	high
139453	SUSE SLES12 Security Update : LibVNCServer (SUSE-SU-2020:2167-1)	Nessus	SuSE Local Security Checks	2020/8/10	2024/2/26	critical
141301	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Vino vulnerabilities (USN-4573-1)	Nessus	Ubuntu Local Security Checks	2020/10/8	2024/8/27	critical
142357	EulerOS 2.0 SP2 : libvncserver (EulerOS-SA-2020-2362)	Nessus	Huawei Local Security Checks	2020/11/3	2022/5/11	high
157648	AlmaLinux 8 : libvncserver (ALSA-2021:1811)	Nessus	Alma Linux Local Security Checks	2022/2/9	2023/11/10	high
184742	Rocky Linux 8 : libvncserver (RLSA-2021:1811)	Nessus	Rocky Linux Local Security Checks	2023/11/6	2023/11/6	high

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