CVE-2026-63812: Linux kernel · f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
A patch has been applied to the Linux kernel to fix the incorrect handling of the FI_NO_EXTENT flag in __destroy_extent_node(). Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data, so check the vendor advisory for current remediation guidance.
Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node() When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does not reset the length of the largest extent to 0 and update the inode folio. Since modifications to the extent tree are disallowed afterward, the cached largest extent may become stale. This can trigger the following error in xfstests generic/388: F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix In the f2fs_drop_inode path, __destroy_extent_node() does not need to guarantee that et->node_cnt is 0, because concurrency with writeback is expected in this path, and writeback may update the extent cache. This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback"), and remove the unnecessary zero check of et->node_cnt.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63812 (opens in a new tab)
- git.kernel.org/stable/c/1f70ddb28a3c71df124da5fa4040c808116d6bb9 (opens in a new tab)
- git.kernel.org/stable/c/20190e498057997532c7f186d081011f18e0a462 (opens in a new tab)
- git.kernel.org/stable/c/58a5deb220bcac4c73bf58954c0845644c997487 (opens in a new tab)
- git.kernel.org/stable/c/7e4d8f98be63f98856a5176b9188dada6e7ba9ee (opens in a new tab)
- git.kernel.org/stable/c/edf12cbeeeabe799bd2ee21fdb5c336cce6fbad7 (opens in a new tab)