What’s Vulnerable › Vulnerabilities

CVE-2022-26356

• Severity: medium (CVSS 5.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-04-05 · updated 2026-06-17
• Weakness: CWE-667

Description

Racy interactions between dirty vram tracking and paging log dirty hypercalls Activation of log dirty mode done by XEN_DMOP_track_dirty_vram (was named HVMOP_track_dirty_vram before Xen 4.9) is racy with ongoing log dirty hypercalls. A suitably timed call to XEN_DMOP_track_dirty_vram can enable log dirty while another CPU is still in the process of tearing down the structures related to a previously enabled log dirty mode (XEN_DOMCTL_SHADOW_OP_OFF). This is due to lack of mutually exclusive locking between both operations and can lead to entries being added in already freed slots, resulting in a memory leak.

Affected products

• Debian Linux: 11.0
• Fedoraproject Fedora: 34, 35
• xen: from 4.0.0 before 4.12.0; from 4.13.0 before 4.14.0; from 4.15.0 before 4.16.0 — fixed in 4.12.0, 4.14.0, 4.16.0

How to fix

Upgrade to a fixed version: xen 4.12.0, 4.14.0, 4.16.0. Check the vendor advisory for mitigations.

References

• http://www.openwall.com/lists/oss-security/2022/04/05/1
• http://xenbits.xen.org/xsa/advisory-397.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6ETPM2OVZZ6KOS2L7QO7SIW6XWT5OW3F/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UHFSRVLM2JUCPDC2KGB7ETPQYJLCGBLD/
• https://security.gentoo.org/glsa/202402-07
• https://www.debian.org/security/2022/dsa-5117
• https://xenbits.xenproject.org/xsa/advisory-397.txt
• http://www.openwall.com/lists/oss-security/2022/04/05/1
• http://xenbits.xen.org/xsa/advisory-397.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6ETPM2OVZZ6KOS2L7QO7SIW6XWT5OW3F/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UHFSRVLM2JUCPDC2KGB7ETPQYJLCGBLD/
• https://security.gentoo.org/glsa/202402-07

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