CVE-2026-63818
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 8.4 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.14% probability · 4th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/210c210c92d78fdf5051bc55c5c69044b1a2150a
- https://git.kernel.org/stable/c/2e12381d4495dc8b0ff042c6856022b2e359835c
- https://git.kernel.org/stable/c/550511a2470f6d204fa07b331f048bd2d3c51280
- https://git.kernel.org/stable/c/846c499a65816d13f1186e3090e825e8bb8bcb8b
- https://git.kernel.org/stable/c/8aad54746c251f2c2370118df766c0c82e2d2091
- https://git.kernel.org/stable/c/ad101d15716f5a24d1fa82a849f80430c805a3dd
- https://git.kernel.org/stable/c/d18c81f5d0ecd5796aa47d66d98f2dd54d8d0f70
- https://git.kernel.org/stable/c/d2f236196d542ccd8505736e41c3a1d3f0305f6f
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.