CVE-2026-89841

7.8 HIGH

Published 2026-09-16 · Updated 2026-09-16

AI risk analysis

Summary: This flaw in the Linux f2fs file system allows for potential over-release of page references, leading to a 'BUG: Bad page state' error and potential system instability.
Exploitability: Exploitation requires the vulnerability to be triggered, which could happen under specific readahead conditions. Exploitability is moderate due to the need for a specific scenario to be met.
Blast radius: If exploited, the impact is limited to the local system, potentially causing system crashes or instability.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to the Linux kernel version 5.18.27 or later.

local-privilege-escalationfile-systemlinuxkernel

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

In the Linux kernel, the following vulnerability has been resolved: f2fs: only redirty pinned folios in redirty_blocks redirty_blocks() pins folios with read_cache_folio() and then walks the same range again with filemap_lock_folio() to redirty them and drop the references it took. Commit 5951fee46bef ("f2fs: Use a folio in redirty_blocks()") changed the second pass to a do/while loop. If read_cache_folio() fails before anything is pinned, page_idx does not advance but the cleanup loop still runs once. If readahead has already populated the failed folio in page cache, that extra iteration finds it and folio_put_refs(folio, 2) drops one reference too many. Later drop_caches or reclaim can then report "BUG: Bad page state". Only redirty the range that was pinned successfully.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Data: NVD (public domain). Analysis: local $0 model. Defensive use only.