Any guest issuing a Xenstore command accessing a node using the (illegal) node path "/local/domain/", will crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with NDEBUG #defined, an unprivileged guest trying to access the node path "/local/domain/" will result in it no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored will use up all cpu time it can get.

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6424 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6424-1                   security@debian.org     https://www.debian.org/security/                       Moritz Muehlenhoff     August 09, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : xen     CVE ID         : CVE-2025-10263 CVE-2025-54505 CVE-2025-54518 CVE-2026-23554                      CVE-2026-23555 CVE-2026-23556 CVE-2026-23557 CVE-2026-23558                      CVE-2026-42487 CVE-2026-42488 CVE-2026-42489 CVE-2026-42490                      CVE-2026-42493 CVE-2026-42494 CVE-2026-42495 CVE-2026-62423                      CVE-2026-62424 CVE-2026-62425 CVE-2026-62426 CVE-2026-62427                      CVE-2026-62428 CVE-2026-62429 CVE-2026-62430 CVE-2026-62431                      CVE-2026-62432 CVE-2026-62433 CVE-2026-62434 CVE-2026-62435                      CVE-2026-62436

    Multiple vulnerabilities have been discovered in the Xen hypervisor,     which could result in privilege escalation, information disclosure or     denial of service.

    For the stable distribution (trixie), these problems have been fixed in     version 4.20.3+127-gc42374a105-0+deb13u1.

    We recommend that you upgrade your xen packages.

    For the detailed security status of xen please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/xen

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

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

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

Any guest issuing a Xenstore command accessing a node using the (illegal) node path '/local/domain/', will crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with NDEBUG #defined, an unprivileged guest trying to access the node path '/local/domain/' will result in it no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored will use up all cpu time it can get.

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

The remote Fedora 42 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-f04da48123 advisory.

    update to xen 4.19.5

    ----

    Use after free of paging structures in EPT [XSA-480, CVE-2026-23554]     Xenstored DoS by unprivileged domain [XSA-481, CVE-2026-23555]


Tenable has extracted the preceding description block directly from the Fedora 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 Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-f884fd0313 advisory.

    update to xen 4.21.1

    ----

    Use after free of paging structures in EPT [XSA-480, CVE-2026-23554]     Xenstored DoS by unprivileged domain [XSA-481, CVE-2026-23555]


Tenable has extracted the preceding description block directly from the Fedora 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 SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:1093-1 advisory.

    - CVE-2026-23554: xen: Use after free of paging structures in EPT (bsc#1259247, XSA-480)
    - CVE-2026-23555: xen: Xenstored DoS by unprivileged domain (bsc#1259248, XSA-481)

Tenable has extracted the preceding description block directly from the SUSE 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 Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-8ae1a1c3d7 advisory.

    Use after free of paging structures in EPT [XSA-480, CVE-2026-23554]     Xenstored DoS by unprivileged domain [XSA-481, CVE-2026-23555]

Tenable has extracted the preceding description block directly from the Fedora 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 SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:0908-1 advisory.

    - CVE-2026-23554: xen: Use after free of paging structures in EPT (bsc#1259247, XSA-480)
    - CVE-2026-23555: xen: Xenstored DoS by unprivileged domain (bsc#1259248, XSA-481)

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

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

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

  - The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m
    lock is dropped, so that multiple modifications done under the same locked region only issue a single
    flush. Freeing of paging structures however is not deferred until the flushing is done, and can result in
    freed pages transiently being present in cached state. Such stale entries can point to memory ranges not
    owned by the guest, thus allowing access to unintended memory regions. (CVE-2026-23554)

  - Any guest issuing a Xenstore command accessing a node using the (illegal) node path "/local/domain/", will
    crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that
    the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with
    NDEBUG #defined, an unprivileged guest trying to access the node path "/local/domain/" will result in it
    no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored
    will use up all cpu time it can get. (CVE-2026-23555)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Any guest issuing a Xenstore command accessing a node using the (illegal) node path /local/domain/, will     crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that     the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with     NDEBUG #defined, an unprivileged guest trying to access the node path /local/domain/ will result in it     no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored     will use up all cpu time it can get. (CVE-2026-23555)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
333555	Debian dsa-6424 : libxen-dev - security update	Nessus	Debian Local Security Checks	Local	critical
318808	Xen: Xenstored DoS by unprivileged domain (XSA-481)	Nessus	Misc.	Local	high
304454	Fedora 42 : xen (2026-f04da48123)	Nessus	Fedora Local Security Checks	Local	high
304345	Fedora 44 : xen (2026-f884fd0313)	Nessus	Fedora Local Security Checks	Local	high
304123	SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2026:1093-1)	Nessus	SuSE Local Security Checks	Local	high
303312	Fedora 43 : xen (2026-8ae1a1c3d7)	Nessus	Fedora Local Security Checks	Local	high
302848	SUSE SLES15: xen / xen-devel / xen-doc-html / xen-libs / xen-libs-32bit / etc (SUSE-SU-2026:0908-1)	Nessus	SuSE Local Security Checks	Local	high
438882	Alpine: multiple xen packages: security update to 4.20.2-r2	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	high
438882	Alpine: multiple xen packages: security update to 4.20.2-r2	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	high
438881	Alpine: multiple xen packages: security update to 4.19.4-r2	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	high
438881	Alpine: multiple xen packages: security update to 4.19.4-r2	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	high
438880	Alpine: multiple xen packages: security update to 4.18.5-r5	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	high
438880	Alpine: multiple xen packages: security update to 4.18.5-r5	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	high
302813	Linux Distros Unpatched Vulnerability : CVE-2026-23555	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-23555

high

Tenable Plugins

critical

high

high

high

high

high

high

high

high

high

high

high

high

high