Mishandling of guest SSBD selection on AMD hardware The current logic to set SSBD on AMD Family 17h and Hygon Family 18h processors requires that the setting of SSBD is coordinated at a core level, as the setting is shared between threads. Logic was introduced to keep track of how many threads require SSBD active in order to coordinate it, such logic relies on using a per-core counter of threads that have SSBD active. When running on the mentioned hardware, it's possible for a guest to under or overflow the thread counter, because each write to VIRT_SPEC_CTRL.SSBD by the guest gets propagated to the helper that does the per-core active accounting. Underflowing the counter causes the value to get saturated, and thus attempts for guests running on the same core to set SSBD won't have effect because the hypervisor assumes it's already active.

The remote host is affected by the vulnerability described in GLSA-202409-10 (Xen: Multiple Vulnerabilities)

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

Tenable has extracted the preceding description block directly from the Gentoo 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 SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:2535-1 advisory.

  - x86 shadow paging arbitrary pointer dereference In environments where host assisted address translation is     necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode.
    Due to too lax a check in one of the hypervisor routines used for shadow page handling it is possible for     a guest with a PCI device passed through to cause the hypervisor to access an arbitrary pointer partially     under guest control. (CVE-2022-42335)

  - Mishandling of guest SSBD selection on AMD hardware The current logic to set SSBD on AMD Family 17h and     Hygon Family 18h processors requires that the setting of SSBD is coordinated at a core level, as the     setting is shared between threads. Logic was introduced to keep track of how many threads require SSBD     active in order to coordinate it, such logic relies on using a per-core counter of threads that have SSBD     active. When running on the mentioned hardware, it's possible for a guest to under or overflow the thread     counter, because each write to VIRT_SPEC_CTRL.SSBD by the guest gets propagated to the helper that does     the per-core active accounting. Underflowing the counter causes the value to get saturated, and thus     attempts for guests running on the same core to set SSBD won't have effect because the hypervisor assumes     it's already active. (CVE-2022-42336)

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 38 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-8334fe0ecb advisory.

    Mishandling of guest SSBD selection on AMD hardware     [XSA-431, CVE-2022-42336]


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.

ID	Name	Product	Family	Severity
207559	GLSA-202409-10 : Xen: Multiple Vulnerabilities	Nessus	Gentoo Local Security Checks	high
177438	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:2535-1)	Nessus	SuSE Local Security Checks	high
176428	Fedora 38 : xen (2023-8334fe0ecb)	Nessus	Fedora Local Security Checks	low

Detections

Analytics

CVE-2022-42336

low

Tenable Plugins

high

high

low