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CVE-2026-63952

8.4 high SSVC exploitation: none Analyzed

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

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 5

  1. Cpes+6 CPE criteria (now 6)NVD modified 2026-10-28 18:09
  2. StatusPublished → AnalyzedNVD modified 2026-10-28 18:09
  3. StatusAwaiting Analysis → PublishedNVD modified 2026-10-19 20:17
  4. CwesCWE-362NVD modified 2026-10-19 21:17
  5. 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