# CVE-2022-42332: xen: x86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is necessary bu...

CVE-2022-42332 is fixed in xen on 1 platform, first by DEBIAN-CVE-2022-42332, released March 21, 2023. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2022-42332
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 21, 2023

## Description

x86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode. Shadow mode maintains a pool of memory used for both shadow page tables as well as auxiliary data structures. To migrate or snapshot guests, Xen additionally runs them in so called log-dirty mode. The data structures needed by the log-dirty tracking are part of aformentioned auxiliary data. In order to keep error handling efforts within reasonable bounds, for operations which may require memory allocations shadow mode logic ensures up front that enough memory is available for the worst case requirements. Unfortunately, while page table memory is properly accounted for on the code path requiring the potential establishing of new shadows, demands by the log-dirty infrastructure were not taken into consideration. As a result, just established shadow page tables could be freed again immediately, while other code is still accessing them on the assumption that they would remain allocated.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | xen Debian 12.15 (bookworm) | 4.17.0+74-g3eac216e6e-1 | [DEBIAN-CVE-2022-42332](https://patchblox.com/security/data/fix/linux/debian-cve-2022-42332.md) | Mar 21, 2023 |
| Linux | xen Debian 13.5 (trixie) | 4.17.0+74-g3eac216e6e-1 | [DEBIAN-CVE-2022-42332](https://patchblox.com/security/data/fix/linux/debian-cve-2022-42332.md) | Mar 21, 2023 |
| Linux | xen Debian 14 | 4.17.0+74-g3eac216e6e-1 | [DEBIAN-CVE-2022-42332](https://patchblox.com/security/data/fix/linux/debian-cve-2022-42332.md) | Mar 21, 2023 |

---

Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.