There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - An issue was discovered in Xen through 4.14.x. In the Ocaml xenstored implementation, the internal
    representation of the tree has special cases for the root node, because this node has no parent.
    Unfortunately, permissions were not checked for certain operations on the root node. Unprivileged guests
    can get and modify permissions, list, and delete the root node. (Deleting the whole xenstore tree is a
    host-wide denial of service.) Achieving xenstore write access is also possible. All systems using
    oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution,
    if the Ocaml compiler is available. Systems using C xenstored are not vulnerable. (CVE-2020-29479)

  - An issue was discovered in Xen through 4.14.x. Neither xenstore implementation does any permission checks
    when reporting a xenstore watch event. A guest administrator can watch the root xenstored node, which will
    cause notifications for every created, modified, and deleted key. A guest administrator can also use the
    special watches, which will cause a notification every time a domain is created and destroyed. Data may
    include: number, type, and domids of other VMs; existence and domids of driver domains; numbers of virtual
    interfaces, block devices, vcpus; existence of virtual framebuffers and their backend style (e.g.,
    existence of VNC service); Xen VM UUIDs for other domains; timing information about domain creation and
    device setup; and some hints at the backend provisioning of VMs and their devices. The watch events do not
    contain values stored in xenstore, only key names. A guest administrator can observe non-sensitive domain
    and device lifecycle events relating to other guests. This information allows some insight into overall
    system configuration (including the number and general nature of other guests), and configuration of other
    guests (including the number and general nature of other guests' devices). This information might be
    commercially interesting or might make other attacks easier. There is not believed to be exposure of
    sensitive data. Specifically, there is no exposure of VNC passwords, port numbers, pathnames in host and
    guest filesystems, cryptographic keys, or within-guest data. (CVE-2020-29480)

  - An issue was discovered in Xen through 4.14.x. Access rights of Xenstore nodes are per domid.
    Unfortunately, existing granted access rights are not removed when a domain is being destroyed. This means
    that a new domain created with the same domid will inherit the access rights to Xenstore nodes from the
    previous domain(s) with the same domid. Because all Xenstore entries of a guest below
    /local/domain/<domid> are being deleted by Xen tools when a guest is destroyed, only Xenstore entries of
    other guests still running are affected. For example, a newly created guest domain might be able to read
    sensitive information that had belonged to a previously existing guest domain. Both Xenstore
    implementations (C and Ocaml) are vulnerable. (CVE-2020-29481)

  - An issue was discovered in Xen through 4.14.x. A guest may access xenstore paths via absolute paths
    containing a full pathname, or via a relative path, which implicitly includes /local/domain/$DOMID for
    their own domain id. Management tools must access paths in guests' namespaces, necessarily using absolute
    paths. oxenstored imposes a pathname limit that is applied solely to the relative or absolute path
    specified by the client. Therefore, a guest can create paths in its own namespace which are too long for
    management tools to access. Depending on the toolstack in use, a malicious guest administrator might cause
    some management tools and debugging operations to fail. For example, a guest administrator can cause
    "xenstore-ls -r" to fail. However, a guest administrator cannot prevent the host administrator from
    tearing down the domain. All systems using oxenstored are vulnerable. Building and using oxenstored is the
    default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored
    are not vulnerable. (CVE-2020-29482)

根据其自我报告的版本号，远程主机上安装的 Xen 虚拟机监控程序受到拒绝服务漏洞影响，这是处理 IRQ 矢量时出现问题所致。在 CPU 之间移动 IRQ 以分配 IRQ 处理负载时，系统会在相关 CPU 上动态分配和取消分配 IRQ 矢量。在满足特定限制时，必须取消分配。如果首次检查时未能符合这些条件，则检查 CPU 可能会向自己发送中断信号，希望此 IRQ 将仅在防止清理的条件被清除之后才会下达。两个特定 IRQ 矢量违背了此预期，导致连续自中断流，进而使得 CPU 实际上无法使用。具有透传 PCI 设备的域可造成物理 CPU 锁定，从而导致整个主机出现拒绝服务 (DoS)。只有 x86 系统易受影响。Arm 系统不易受影响。只有向其透传物理 PCI 设备的才能利用此漏洞。

请注意，Nessus 尚未测试此问题，而是只依赖于应用程序自我报告的版本号。

远程主机受到 GLSA-202107-30 中所述漏洞的影响（Xen：多个漏洞）

    已在 Xen 中发现多个漏洞。请检查下方引用的 CVE 标识符以了解详细信息。
  影响：

    请查看供参考的 CVE 标识符，了解详细信息。
  变通方案：

    目前无任何已知的变通方案。

根據其自我報告的版本號碼判斷，遠端主機上安裝的 Xen Hypervisor 受到拒絕服務弱點影響，這是因為在處理 IRQ 向量時發生問題所導致。當在 CPU 之間移動 IRQ 以分散 IRQ 處理的負載時，應用程式會在相關 CPU 上動態配置和取消配置 IRQ 向量。符合特定限制時，必須解除配置。如果在第一次檢查時不符合這些條件，檢查 CPU 可能會傳送一個中斷給自己，預期此 IRQ 只會在防止清除的條件清除後傳送。若是兩個特定的 IRQ 向量，則會違背此預期，進而導致連續的自我中斷資料流，造成 CPU 實際上無法使用。具有傳遞 PCI 裝置的網域可造成實體 CPU 鎖定，進而導致整個主機發生拒絕服務 (DoS)。僅 x86 系統會受到影響。Arm 系統不受影響。只有收到實體 PCI 裝置傳遞的來賓可惡意利用此弱點。

請注意，Nessus 並未測試此問題，而是僅依據應用程式自我報告的版本號碼。

遠端主機受到 GLSA-202107-30 中所述的弱點影響 (Xen：多個弱點)

    在 Xen 中發現多個弱點。如需詳細資訊，請檢閱下方提及的 CVE 識別碼。
  影響：

    如需詳細資料，請檢閱提及的 CVE 識別碼。
  因應措施：

    目前尚無已知的因應措施。

権限チェックのないxenstoreウォッチ通知[XSA-115、CVE-2020-29480]（#1908091）Xenstore：既存のノード権限を継承する新しいドメイン[XSA-322、CVE-2020-29481]（#1908095）Xenstore：不適切なパス長チェック[XSA-323、CVE-2020-29482]（#1908096）Xenstore：
ゲストがwatchによりxenstoredをクラッシュさせる可能性があります[XSA-324、CVE-2020-29484]（#1908088）Xenstore：ゲストがドメインのクリーンアップを妨げる可能性がある[XSA-325、CVE-2020-29483]（#1908087）reset_watchesのoxenstoredメモリリーク[XSA-330、CVE-2020-29485]（#1908000）x86 HVMコンテキストスイッチコードの不適切な再帰[XSA-348、CVE-2020-29566]（#1908085）oxenstored：
ノードの所有権は、権限のないクライアントによって変更される可能性があります[XSA-352、CVE-2020-29486]（#1908003）oxenstored：rootノードで権限がチェックされない[XSA-353、CVE-2020-29479]（#1908002）IRQベクトルをクリーンアップするときの無限ループ[XSA-356、CVE-2020-29567]（#1907932）FIFOイベントチャネルコントロールブロック関連の順序[XSA-358、CVE-2020-29570]（#1907931）FIFOイベントチャネル制御構造の順序[XSA-359、CVE-2020-29571]（#1908089）

注意：Tenable Network Securityは、前述の記述ブロックをFedora更新システムのWebサイトから直接抽出しています。
Tenableでは、新たな問題を持ち込まずに、できる限り自動的に整理して書式設定するようにしています。

自己報告によるバージョン番号によると、リモートにインストールされているXenハイパーバイザーは、IRQベクトル処理時の問題によりサービス拒否の脆弱性の影響を受けます。CPU間でIRQを移動してIRQ処理の負荷を分散させると、IRQベクトルが関連するCPUで動的に割り当て/割り当て解除されます。特定の制約が満たされたときに割り当て解除が発生する必要があります。最初にチェックしたときにこれらの条件が満たされていないと、クリーンアップを妨げる条件がクリアされた後にのみこのIRQが送信されることを期待して、チェックを行うCPUが自身に割り込みを送信することがあります。2つの特定のIRQベクトルの場合、この期待が違反され、自己割り込みの連続ストリームが発生し、CPUを事実上使用できなくしました。パススルーされたPCIデバイスを持つドメインは、物理CPUのロックアップを引き起こし、ホスト全体に対してサービス拒否（DoS）を引き起こす可能性があります。x86システムにのみ脆弱性があります。ARMシステムには脆弱性はありません。物理的なPCIデバイスを渡されたゲストのみが、この脆弱性を悪用できます。

Nessusはこの問題をテストしておらず、代わりにアプリケーションの自己報告されたバージョン番号にのみ依存しています。

The remote host is affected by the vulnerability described in GLSA-202107-30 (Xen: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Xen. Please review the       CVE identifiers referenced below for details.
  Impact :

    Please review the referenced CVE identifiers for details.
  Workaround :

    There is no known workaround at this time.

xenstore watch notifications lacking permission checks [XSA-115, CVE-2020-29480] (#1908091) Xenstore: new domains inheriting existing node permissions [XSA-322, CVE-2020-29481] (#1908095) Xenstore: wrong path length check [XSA-323, CVE-2020-29482] (#1908096) Xenstore:
guests can crash xenstored via watchs [XSA-324, CVE-2020-29484] (#1908088) Xenstore: guests can disturb domain cleanup [XSA-325, CVE-2020-29483] (#1908087) oxenstored memory leak in reset_watches [XSA-330, CVE-2020-29485] (#1908000) undue recursion in x86 HVM context switch code [XSA-348, CVE-2020-29566] (#1908085) oxenstored:
node ownership can be changed by unprivileged clients [XSA-352, CVE-2020-29486] (#1908003) oxenstored: permissions not checked on root node [XSA-353, CVE-2020-29479] (#1908002) infinite loop when cleaning up IRQ vectors [XSA-356, CVE-2020-29567] (#1907932) FIFO event channels control block related ordering [XSA-358, CVE-2020-29570] (#1907931) FIFO event channels control structure ordering [XSA-359, CVE-2020-29571] (#1908089)

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

According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by a denial of service vulnerability due to an issue when handling IRQ vectors. When moving IRQs between CPUs to distribute the load of IRQ handling, IRQ vectors are dynamically allocated and de-allocated on the relevant CPUs. De-allocation has to happen when certain constraints are met. If these conditions are not met when first checked, the checking CPU may send an interrupt to itself, in the expectation that this IRQ will be delivered only after the condition preventing the cleanup has cleared. For two specific IRQ vectors, this expectation was violated, resulting in a continuous stream of self-interrupts, which renders the CPU effectively unusable. A domain with a passed through PCI device can cause lockup of a physical CPU, resulting in a Denial of Service (DoS) to the entire host. Only x86 systems are vulnerable. Arm systems are not vulnerable. Only guests with physical PCI devices passed through to them can exploit the vulnerability.

Note that Nessus has not tested for this issue 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
400301	Alpine: multiple xen packages: security update to 4.14.0-r3 (deprecated)	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	2023/8/16	2026/7/2	high
424699	Alpine: multiple xen packages: security update to 4.14.1-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	2025/4/4	2026/7/2	high
424699	Alpine: multiple xen packages: security update to 4.14.1-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	2025/4/4	2026/7/2	high
400301	Alpine: multiple xen packages: security update to 4.14.0-r3 (deprecated)	Tenable Cloud Security	Alpine Linux Local Security Checks	2023/8/16	2026/7/2	high
144743	Xen IRQ 无限循环 DoS (XSA-356)	Nessus	Misc.	2021/1/5	2021/6/3	medium
157004	GLSA-202107-30：Xen：多个漏洞	Nessus	Gentoo Local Security Checks	2022/1/24	2022/1/26	high
144743	Xen IRQ 無限迴圈 DoS (XSA-356)	Nessus	Misc.	2021/1/5	2021/6/3	medium
157004	GLSA-202107-30：Xen：多個弱點	Nessus	Gentoo Local Security Checks	2022/1/24	2022/1/26	high
144611	Fedora 33：xen（2020-64859a826b）	Nessus	Fedora Local Security Checks	2020/12/28	2024/1/31	high
144743	Xen IRQ Infinite LoopのDoS（XSA-356）	Nessus	Misc.	2021/1/5	2021/6/3	medium
157004	GLSA-202107-30 : Xen: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	2022/1/24	2022/1/26	high
144611	Fedora 33 : xen (2020-64859a826b)	Nessus	Fedora Local Security Checks	2020/12/28	2024/1/31	high
144743	Xen IRQ Infinite Loop DoS (XSA-356)	Nessus	Misc.	2021/1/5	2021/6/3	medium

检测

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