[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] With the introduction of Grant Table v2 came the requirement to be able to switch between versions. Switching from v1 to v2 reduces the number of valid grant references, as a bigger shared entry structure is then needed while the shared table doesn't change size. Switching from v2 back to v1 the status frames, which are separate in v2, go away. Code holding, but intermediately dropping and then re-acquiring the grant table lock, sometimes wrongly assumes that said properties wouldn't change across the window in time where the lock is not being held. The v1 -> v2 issue is CVE-2026-62435. The v2 -> v1 issue is CVE-2026-62436.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-9b1af4c793 advisory.

    update to xen 4.20.4     includes security fixes     x86 shadow paging is deprecated [XSA-495, CVE-2026-42493]     vIRQ event channel binding may break Xenstore [XSA-496, CVE-2026-42492]     buffer overruns in libfsimage iso9660 handling [XSA-497, CVE-2026-42494,     CVE-2026-42495, CVE-2026-62423, CVE-2026-62424, CVE-2026-62425]     sysctl and platform-op locks open to abuse [XSA-499, CVE-2026-62426,     CVE-2026-62427]     grant-table: type confusion in grant-copy [XSA-500, CVE-2026-62428]     grant-table: version change racing with other operations [XSA-501,     CVE-2026-62435, CVE-2026-62436]     vNUMA domain cleanup may race other operations [XSA-502, CVE-2026-62429]     x86: Out-of-bounds read in vRTC emulation [XSA-503, CVE-2026-62430]     Viridian STIMER division by zero [XSA-504, CVE-2026-62431]     evtchn: Race between FIFO expand and reset [XSA-505, CVE-2026-62432]     correct buffer checks for DM_OP hypercalls [XSA-506, CVE-2026-62433]     PoD: Don't try to reclaim special pages [XSA-507, CVE-2026-62434]     pygrub is only supported in de-privileged mode [XSA-508]     x86 HVM I/O port list traversal [XSA-491, CVE-2026-42487]     domctl lock open to abuse [XSA-492, CVE-2026-42489, CVE-2026-42490]     Arm: Completion of memory accesses not guaranteed by completion of a TLBI     [XSA-493, CVE-2025-10263]     x86: mismatched mapcache metadata [XSA-494, CVE-2026-42488]

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 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.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-bf1da84dfc advisory.

    update to xen 4.21.2     includes security fixes     x86 shadow paging is deprecated [XSA-495, CVE-2026-42493]     vIRQ event channel binding may break Xenstore [XSA-496, CVE-2026-42492]     buffer overruns in libfsimage iso9660 handling [XSA-497, CVE-2026-42494,     CVE-2026-42495, CVE-2026-62423, CVE-2026-62424, CVE-2026-62425]     sysctl and platform-op locks open to abuse [XSA-499, CVE-2026-62426,     CVE-2026-62427]     grant-table: type confusion in grant-copy [XSA-500, CVE-2026-62428]     grant-table: version change racing with other operations [XSA-501,     CVE-2026-62435, CVE-2026-62436]     vNUMA domain cleanup may race other operations [XSA-502, CVE-2026-62429]     x86: Out-of-bounds read in vRTC emulation [XSA-503, CVE-2026-62430]     Viridian STIMER division by zero [XSA-504, CVE-2026-62431]     evtchn: Race between FIFO expand and reset [XSA-505, CVE-2026-62432]     correct buffer checks for DM_OP hypercalls [XSA-506, CVE-2026-62433]     PoD: Don't try to reclaim special pages [XSA-507, CVE-2026-62434]     pygrub is only supported in de-privileged mode [XSA-508]

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

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] With the introduction of Grant Table v2 came the requirement to be able to     switch between versions. Switching from v1 to v2 reduces the number of valid grant references, as a bigger     shared entry structure is then needed while the shared table doesn't change size. Switching from v2 back     to v1 the status frames, which are separate in v2, go away. Code holding, but intermediately dropping and     then re-acquiring the grant table lock, sometimes wrongly assumes that said properties wouldn't change     across the window in time where the lock is not being held. The v1 -> v2 issue is CVE-2026-62435. The v2
    -> v1 issue is CVE-2026-62436. (CVE-2026-62436)

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

ID	Name	Product	Family	Type	Severity
334454	Fedora 43 : xen (2026-9b1af4c793)	Nessus	Fedora Local Security Checks	Local	high
333555	Debian dsa-6424 : libxen-dev - security update	Nessus	Debian Local Security Checks	Local	critical
331597	Fedora 44 : xen (2026-bf1da84dfc)	Nessus	Fedora Local Security Checks	Local	high
330471	Linux Distros Unpatched Vulnerability : CVE-2026-62436	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2026-62436

medium

Tenable Plugins

high

critical

high

medium