CVE-2026-89834
f2fs: fix to migrate all curseg types during free_segment_range
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.
INFO
Published Date :
Sept. 16, 2026, 11:16 a.m.
Last Modified :
Sept. 16, 2026, 11:16 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest version.
- Apply the patch for f2fs segment migration.
- Verify filesystem integrity after update.
References to Advisories, Solutions, and Tools
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CVE-2026-89834.
CWE - Common Weakness Enumeration
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specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89834 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-89834
weaknesses.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 16, 2026
Action Type Old Value New Value Added 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89834.json">CVE-2026-89834</a> Added Reference https://git.kernel.org/stable/c/3b85edf3391f3e1f624f409a7d2d239885f567b7 Added Reference https://git.kernel.org/stable/c/8ec06f50ddd8d201bd7e55b896ae28ed9d4cb7d1 Added Reference https://git.kernel.org/stable/c/b8ae1228c153622afa71a179c9d4dc268117e0f0 Added Reference https://git.kernel.org/stable/c/b9776094aa7118e8e5dfdcd791ffc8330c5ca408