# CVE-2022-49554: linux: In the Linux kernel, the following vulnerability has been resolved:  zsmalloc: fix races between asynchronous zspage...

CVE-2022-49554 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49554, released February 26, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-49554
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 26, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  zsmalloc: fix races between asynchronous zspage free and page migration  The asynchronous zspage free worker tries to lock a zspage's entire page list without defending against page migration.  Since pages which haven't yet been locked can concurrently migrate off the zspage page list while lock_zspage() churns away, lock_zspage() can suffer from a few different lethal races.  It can lock a page which no longer belongs to the zspage and unsafely dereference page_private(), it can unsafely dereference a torn pointer to the next page (since there's a data race), and it can observe a spurious NULL pointer to the next page and thus not lock all of the zspage's pages (since a single page migration will reconstruct the entire page list, and create_page_chain() unconditionally zeroes out each list pointer in the process).  Fix the races by using migrate_read_lock() in lock_zspage() to synchronize with page migration.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.18.2-1 | [DEBIAN-CVE-2022-49554](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49554.md) | Feb 26, 2025 |
| Linux | linux Debian 13.5 (trixie) | 5.18.2-1 | [DEBIAN-CVE-2022-49554](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49554.md) | Feb 26, 2025 |
| Linux | linux Debian 14 | 5.18.2-1 | [DEBIAN-CVE-2022-49554](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49554.md) | Feb 26, 2025 |

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Data as of 2026-11-08T00:53:09Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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