# CVE-2022-23034: xen: A PV guest could DoS Xen while unmapping a grant To address XSA-380, reference counting was introduced for grant mapp...

CVE-2022-23034 is fixed in xen on 1 platform, first by DEBIAN-CVE-2022-23034, released January 25, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-23034
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0034
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 25, 2022

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | xen Debian 12.15 (bookworm) | 4.16.0+51-g0941d6cb-1 | [DEBIAN-CVE-2022-23034](https://patchblox.com/security/data/fix/linux/debian-cve-2022-23034.md) | Jan 25, 2022 |
| Linux | xen Debian 13.5 (trixie) | 4.16.0+51-g0941d6cb-1 | [DEBIAN-CVE-2022-23034](https://patchblox.com/security/data/fix/linux/debian-cve-2022-23034.md) | Jan 25, 2022 |
| Linux | xen Debian 14 | 4.16.0+51-g0941d6cb-1 | [DEBIAN-CVE-2022-23034](https://patchblox.com/security/data/fix/linux/debian-cve-2022-23034.md) | Jan 25, 2022 |

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