# CVE-2026-97534: f2fs: accurately adjust free_sections during free_segment_range

CVE-2026-97534 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-97534, released October 2, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-97534
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 25, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97534

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-97534](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97534.md) | Oct 2, 2026 |
| Linux | linux Debian 14 | 7.2.7-1 | [DEBIAN-CVE-2026-97534](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97534.md) | Oct 2, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.113-1~deb12u1 | [DEBIAN-CVE-2026-97534](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97534.md) | Oct 2, 2026 |

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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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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