# CVE-2026-89834: linux: In the Linux kernel, the following vulnerability has been resolved:  f2fs: fix to migrate all curseg types during fre...

CVE-2026-89834 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-89834, released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-89834
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 16, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  f2fs: fix to migrate all curseg types during free_segment_range  In free_segment_range(), the curseg evacuation loop only iterates up to NR_CURSEG_PERSIST_TYPE (0..5), missing non-persistent in-memory curseg types such as CURSEG_COLD_DATA_PINNED and CURSEG_ALL_DATA_ATGC.  Even though these in-memory curseg types are not saved in the on-disk checkpoint header, they still occupy active physical segments at runtime. If an active in-memory curseg happens to be allocated within the segment range being truncated during filesystem shrink, failing to evacuate it will cause subsequent writes to the curseg attempting out-of-bounds I/O on the truncated storage range.  Fix this by expanding the curseg evacuation loop upper bound to NR_CURSEG_TYPE to ensure all active curseg types are safely migrated out of the target range.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-89834](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89834.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89834](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89834.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-89834](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89834.md) | Sep 23, 2026 |

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Data as of 2026-11-09T07:25:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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