In the Linux kernel, the following vulnerability has been resolved: memfd: deny writeable mappings when implying SEAL_WRITE When SEAL_EXEC is added, SEAL_WRITE is implied to make W^X. But the implied seal is set after the check that makes sure the memfd can not have any writable mappings. This means one can use SEAL_EXEC to apply SEAL_WRITE while having writeable mappings. This breaks the contract that SEAL_WRITE provides and can be used by an attacker to pass a memfd that appears to be write sealed but can still be modified arbitrarily. Fix this by adding the implied seals before the call for mapping_deny_writable() is done.
Fix
Patch, vendor advisory and mitigation references on NVD 5
- https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08 Patch
- https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222 Patch
- https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4 Patch
- https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8 Patch
- https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e Patch
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 5
- Cpes+6 CPE criteria (now 6)NVD modified 2026-10-28 18:09
- StatusPublished → AnalyzedNVD modified 2026-10-28 18:09
- StatusAwaiting Analysis → PublishedNVD modified 2026-10-19 20:17
- CwesCWE-362NVD modified 2026-10-19 21:17
- First seenCVSS 8.4NVD modified 2026-10-16 16:18
Affected (CPE criteria) 6
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
References 5
- https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08 Patch
- https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222 Patch
- https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4 Patch
- https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8 Patch
- https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e Patch