CVE-2026-63952High· 8.4▾ TwilightIn 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 m…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 46.2 · likelihood 0 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Oct 16.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
0.2%
8.4 → 7
Last analysed / modified upstream
7 → 8.4
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.
Linux >= c4f75bc8bd6b3d62665e1f5400c419540edb5601 < b3f4f82d1315f1439059a83d1c22c51a5b43d99eLinux >= c4f75bc8bd6b3d62665e1f5400c419540edb5601 < 3be2a24f7f72ad7321ed6ad1715b956a4527bcf4Linux >= c4f75bc8bd6b3d62665e1f5400c419540edb5601 < 0995d1f79aed8ccbf62056189dd53fd19726ea08Linux >= c4f75bc8bd6b3d62665e1f5400c419540edb5601 < 555702282d4536a865dfffb1cd4f6028f196e7e8Linux >= c4f75bc8bd6b3d62665e1f5400c419540edb5601 < 3b041514cb6eae45869b020f743c14d983363222Linux 6.3Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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