CVE-2024-39276ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()
- 5.5MediumCVSS base score
- 0.23%Exploitation in 30 daysEPSS · top 86% 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: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() Syzbot reports a warning as follows: ============================================ WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 Modules linked in: CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 Call Trace: <TASK> ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 generic_shutdown_super+0x136/0x2d0 fs/super.c:641 kill_block_super+0x44/0x90 fs/super.c:1675 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 [...] ============================================ This is because when finding an entry in ext4_xattr_block_cache_find(), if ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown in the __entry_find(), won't be put away, and eventually trigger the above issue in mb_cache_destroy() due to reference count leakage. So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.
Timeline
ID reserved
By Linux
- 1 day later
· 1 day later
Published
- 23 months later
· 23 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
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.23% · top 86% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected b878c8a7f08f0c225b6a46ba1ac867e9c5d17807 – < 9ad75e78747b5a50dc5a52f0f8e92e920a653f16
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < 896a7e7d0d555ad8b2b46af0c2fa7de7467f9483
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < 76dc776153a47372719d664e0fc50d6355791abb
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < 681ff9a09accd8a4379f8bd30b7a1641ee19bb3e
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < e941b712e758f615d311946bf98216e79145ccd9
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < a95df6f04f2c37291adf26a74205cde0314d4577
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < b37c0edef4e66fb21a2fbc211471195a383e5ab8
- affected fb265c9cb49e2074ddcdd4de99728aefdd3b3592 – < 0c0b4a49d3e7f49690a6827a41faeffad5df7e21
- affected 9da1f6d06b7a6d068e68fcfd7cbbf6b586d888e1
- affected 81313ed2c705d958744882a269bf4a5e3ddec95e
- affected 4.19.14 – < 4.19.316
- affected 4.14.92 – < 4.15
- affected 4.20.1 – < 4.21
- affected 5.0
- unaffected < 5.0
- unaffected 4.19.316 – ≤ 4.19.*
- unaffected 5.4.278 – ≤ 5.4.*
- unaffected 5.10.219 – ≤ 5.10.*
- unaffected 5.15.161 – ≤ 5.15.*
- unaffected 6.1.94 – ≤ 6.1.*
- unaffected 6.6.34 – ≤ 6.6.*
- unaffected 6.9.5 – ≤ 6.9.*
- unaffected 6.10 – ≤ *
References
References8
- https://git.kernel.org/stable/c/9ad75e78747b5a50dc5a52f0f8e92e920a653f16 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/896a7e7d0d555ad8b2b46af0c2fa7de7467f9483 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/76dc776153a47372719d664e0fc50d6355791abb (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/681ff9a09accd8a4379f8bd30b7a1641ee19bb3e (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/e941b712e758f615d311946bf98216e79145ccd9 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/a95df6f04f2c37291adf26a74205cde0314d4577 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/b37c0edef4e66fb21a2fbc211471195a383e5ab8 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/0c0b4a49d3e7f49690a6827a41faeffad5df7e21 (opens in a new tab)x_transferred
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-2024-38198 (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)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2024-39276)Record last updated .