The fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative Return Stack Overflow) are not IRQ-safe. It was believed that the mitigations always operated in contexts with IRQs disabled. However, the original XSA-254 fix for Meltdown (XPTI) deliberately left interrupts enabled on two entry paths; one unconditionally, and one conditionally on whether XPTI was active. As BTC/SRSO and Meltdown affect different CPU vendors, the mitigations are not active together by default. Therefore, there is a race condition whereby a malicious PV guest can bypass BTC/SRSO protections and launch a BTC/SRSO attack against Xen.

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-2023:4945-1 advisory.

  - x86/AMD: mismatch in IOMMU quarantine page table levels [XSA-445, CVE-2023-46835] x86: BTC/SRSO fixes not     fully effective [XSA-446, CVE-2023-46836] (CVE-2023-46835, CVE-2023-46836)

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 37 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-e62da41072 advisory.

    x86/AMD: mismatch in IOMMU quarantine page table levels [XSA-445,     CVE-2023-46835]     x86: BTC/SRSO fixes not fully effective [XSA-446, CVE-2023-46836]

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 38 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-56901a79a1 advisory.

    x86/AMD: mismatch in IOMMU quarantine page table levels [XSA-445,     CVE-2023-46835]     x86: BTC/SRSO fixes not fully effective [XSA-446, CVE-2023-46836]

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 39 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-fa01e4c6ba advisory.

    x86/AMD: mismatch in IOMMU quarantine page table levels [XSA-445,     CVE-2023-46835]     x86: BTC/SRSO fixes not fully effective [XSA-446, CVE-2023-46836]

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 fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative Return Stack Overflow) are not IRQ-safe as it was believed that the mitigations were always operated in contexts with IRQs disabled. However due to an unanticipated interaction with XSA-254 (Meltdown), a race condition exists whereby a malicious guest can bypass BTC/SRSO protections.
As a result, an attacker in a PV guest can infer the contents of memory belonging to other guests.

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

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4484-1 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 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4485-1 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 SLES12 / SLES_SAP12 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4486-1 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 openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4476-1 advisory.

  - A division-by-zero error on some AMD processors can potentially return speculative data resulting in loss     of confidentiality. (CVE-2023-20588)

  - arm32: The cache may not be properly cleaned/invalidated [XSA-437, CVE-2023-34321] top-level shadow     reference dropped too early for 64-bit PV guests [XSA-438, CVE-2023-34322] x86/AMD: Divide speculative     information leak [XSA-439, CVE-2023-20588] (CVE-2023-34322)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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

The remote openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4475-1 advisory.

  - A division-by-zero error on some AMD processors can potentially return speculative data resulting in loss     of confidentiality. (CVE-2023-20588)

  - arm32: The cache may not be properly cleaned/invalidated [XSA-437, CVE-2023-34321] top-level shadow     reference dropped too early for 64-bit PV guests [XSA-438, CVE-2023-34322] x86/AMD: Divide speculative     information leak [XSA-439, CVE-2023-20588] (CVE-2023-34322)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4466-1 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
187177	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4945-1)	Nessus	SuSE Local Security Checks	medium
186496	Fedora 37 : xen (2023-e62da41072)	Nessus	Fedora Local Security Checks	medium
186460	Fedora 38 : xen (2023-56901a79a1)	Nessus	Fedora Local Security Checks	medium
186457	Fedora 39 : xen (2023-fa01e4c6ba)	Nessus	Fedora Local Security Checks	medium
186415	Xen: x86: BTC/SRSO Fixes Not Fully Effective (XSA-446)	Nessus	Misc.	medium
186026	SUSE SLES15 Security Update : xen (SUSE-SU-2023:4484-1)	Nessus	SuSE Local Security Checks	medium
186023	SUSE SLES15 Security Update : xen (SUSE-SU-2023:4485-1)	Nessus	SuSE Local Security Checks	medium
186022	SUSE SLES12 Security Update : xen (SUSE-SU-2023:4486-1)	Nessus	SuSE Local Security Checks	medium
185977	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4476-1)	Nessus	SuSE Local Security Checks	high
185975	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4475-1)	Nessus	SuSE Local Security Checks	high
185936	SUSE SLES15 Security Update : xen (SUSE-SU-2023:4466-1)	Nessus	SuSE Local Security Checks	medium

Detections

Analytics

CVE-2023-46836

medium

Tenable Plugins

high

medium

medium

medium

medium

medium

medium

medium

medium

high

high

medium