f2fs: validate orphan inode entry count
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: validate orphan inode entry count f2fs_recover_orphan_inodes() trusts the orphan block entry_count when replaying orphan inodes from the checkpoint pack. A corrupted entry_count larger than F2FS_ORPHANS_PER_BLOCK makes the recovery loop read past the ino[] array and interpret footer or following data as inode numbers. On a crafted image, mounting an unpatched kernel can drive orphan recovery into f2fs_bug_on() and panic the kernel. Validate entry_count before consuming entries so corrupted checkpoint data fails the mount with -EFSCORRUPTED and requests fsck instead. Set ERROR_INCONSISTENT_ORPHAN as well, so the corruption reason can be recorded in the superblock s_errors[] field. This gives fsck a persistent hint even though mount-time orphan recovery failure may leave no chance to persist SBI_NEED_FSCK through a checkpoint.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.38, 7.1.3, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-63818
- 2026-10-03 Alias added: GHSA-2q7w-rghx-vwh8
- 2026-10-20 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/210c210c92d78fdf5051bc55c5c69044b1a2150a
- https://git.kernel.org/stable/c/ad101d15716f5a24d1fa82a849f80430c805a3dd
- https://git.kernel.org/stable/c/d18c81f5d0ecd5796aa47d66d98f2dd54d8d0f70
- https://git.kernel.org/stable/c/d2f236196d542ccd8505736e41c3a1d3f0305f6f
- https://git.kernel.org/stable/c/550511a2470f6d204fa07b331f048bd2d3c51280
- https://git.kernel.org/stable/c/8aad54746c251f2c2370118df766c0c82e2d2091
- https://git.kernel.org/stable/c/2e12381d4495dc8b0ff042c6856022b2e359835c
- https://git.kernel.org/stable/c/846c499a65816d13f1186e3090e825e8bb8bcb8b
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Sources
- CVE-2026-63818 · CVE Program
- CVE-2026-63818 · NVD
- FIRST EPSS
- GHSA-2q7w-rghx-vwh8 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-63818 · Red Hat security data · CC BY 4.0
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