CVE-2025-40307exfat: validate cluster allocation bits of the allocation bitmap
- 7.8HighCVSS base score
- 0.16%Exploitation in 30 daysEPSS · top 95% 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: exfat: validate cluster allocation bits of the allocation bitmap syzbot created an exfat image with cluster bits not set for the allocation bitmap. exfat-fs reads and uses the allocation bitmap without checking this. The problem is that if the start cluster of the allocation bitmap is 6, cluster 6 can be allocated when creating a directory with mkdir. exfat zeros out this cluster in exfat_mkdir, which can delete existing entries. This can reallocate the allocated entries. In addition, the allocation bitmap is also zeroed out, so cluster 6 can be reallocated. This patch adds exfat_test_bitmap_range to validate that clusters used for the allocation bitmap are correctly marked as in-use.
Timeline
ID reserved
By Linux
- 8 months later
· 8 months later
Published
- 10 months later
· 10 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 |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Deferred | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.16% · top 95% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – < 87f827d53bd0688597bda63ae95908e2ad39bac0
- affected 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – < 67ce8034dc0278ddd88cad93d4218a945180dddd
- affected 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – < 6bc58b4c53795ab5fe00648344aa7d9d61175f90
- affected 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – < 13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf
- affected 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – < 79c1587b6cda74deb0c86fc7ba194b92958c793c
- affected 5.7
- unaffected < 5.7
- unaffected 6.1.183 – ≤ 6.1.*
- unaffected 6.6.148 – ≤ 6.6.*
- unaffected 6.12.58 – ≤ 6.12.*
- unaffected 6.17.8 – ≤ 6.17.*
- unaffected 6.18 – ≤ *
References
References5
- https://git.kernel.org/stable/c/87f827d53bd0688597bda63ae95908e2ad39bac0 (opens in a new tab)
- https://git.kernel.org/stable/c/67ce8034dc0278ddd88cad93d4218a945180dddd (opens in a new tab)
- https://git.kernel.org/stable/c/6bc58b4c53795ab5fe00648344aa7d9d61175f90 (opens in a new tab)
- https://git.kernel.org/stable/c/13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf (opens in a new tab)
- https://git.kernel.org/stable/c/79c1587b6cda74deb0c86fc7ba194b92958c793c (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-2025-201638 (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-2025-40307)Record last updated .