CVE-2026-74307ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT
- —Not scoredno CVSS score yet
- 0.18%Exploitation in 30 daysEPSS · top 92% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not belong to the same superblock as the original file. Currently, this validation is performed inside ext4_move_extents() by mext_check_validity(), but only after lock_two_nondirectories() has already acquired the inode locks. When the donor fd refers to a file on a different filesystem (e.g., overlayfs), this late validation creates a circular lock dependency: CPU0 (overlayfs write) CPU1 (ext4 ioctl) ---- ---- inode_lock(ovl_inode) mnt_want_write_file(filp) sb_start_write(ext4_sb) [sb_writers] backing_file_write_iter() vfs_iter_write(real_file) file_start_write(real_file) sb_start_write(ext4_sb) [blocked by freeze] lock_two_nondirectories() inode_lock(ovl_inode) [blocked] With a concurrent freeze operation holding sb_writers write side, this forms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock. Since EXT4_IOC_MOVE_EXT exchanges physical extents between two files, it fundamentally requires both files to reside on the same ext4 filesystem. Moving the superblock check before any lock acquisition is both semantically correct and eliminates the circular dependency by ensuring that cross-filesystem donor fds are rejected before sb_writers or inode locks are taken.
Timeline
ID reserved
By Linux
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.18% · top 92% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a – < 23380fc1bf5d3b75dcbd51eb72be4eb0a3300370
- affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a – < 663f184b51492093d408e518efc95ee13b5b4440
- affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a – < 74796e886ca39fcb0d3fd36ea6a39c62784ab6fb
- affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a – < 29e07ec352f0ad06c833a18bf47d82c81f55544f
- affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a – < fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c
- affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a – < c143957520c6c9b5cd72e0de8b52b814f0c576fe
- affected 3.18
- unaffected < 3.18
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.97 – ≤ 6.12.*
- unaffected 6.18.57 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/23380fc1bf5d3b75dcbd51eb72be4eb0a3300370 (opens in a new tab)
- https://git.kernel.org/stable/c/663f184b51492093d408e518efc95ee13b5b4440 (opens in a new tab)
- https://git.kernel.org/stable/c/74796e886ca39fcb0d3fd36ea6a39c62784ab6fb (opens in a new tab)
- https://git.kernel.org/stable/c/29e07ec352f0ad06c833a18bf47d82c81f55544f (opens in a new tab)
- https://git.kernel.org/stable/c/fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c (opens in a new tab)
- https://git.kernel.org/stable/c/c143957520c6c9b5cd72e0de8b52b814f0c576fe (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-59454 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-74307)Record last updated .