Xenstore, to have an up-to-date picture of the entire system, wants to know of domains appearing and disappearing. To make this more robust, a new XEN_DOMCTL_get_domain_state was introduced. The management of the bitmap underlying that operation is tied into the binding of the VIRQ_DOM_EXC virtual IRQ. Unfortunately an error path there would tear down the bitmap even in cases when it wasn't set up. Unprivileged domains can trigger that error path.

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 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.

  - Xenstore, to have an up-to-date picture of the entire system, wants to know of domains appearing and     disappearing. To make this more robust, a new XEN_DOMCTL_get_domain_state was introduced. The management     of the bitmap underlying that operation is tied into the binding of the VIRQ_DOM_EXC virtual IRQ.
    Unfortunately an error path there would tear down the bitmap even in cases when it wasn't set up.
    Unprivileged domains can trigger that error path. (CVE-2026-42492)

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
331597	Fedora 44 : xen (2026-bf1da84dfc)	Nessus	Fedora Local Security Checks	Local	high
330470	Linux Distros Unpatched Vulnerability : CVE-2026-42492	Nessus	Misc.	Local	high

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