CVE-2026-63952
Last modified
CVE-2026-63952 is a high-severity vulnerability rated 8.4/10 on the CVSS scale. 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. EPSS estimates a 0.16% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= c4f75bc8bd6b3d62665e1f5400c419540edb5601, < b3f4f82d1315f1439059a83d1c22c51a5b43d99e; >= c4f75bc8bd6b3d62665e1f5400c419540edb5601, < 3be2a24f7f72ad7321ed6ad1715b956a4527bcf4; >= c4f75bc8bd6b3d62665e1f5400c419540edb5601, < 0995d1f79aed8ccbf62056189dd53fd19726ea08; >= c4f75bc8bd6b3d62665e1f5400c419540edb5601, < 555702282d4536a865dfffb1cd4f6028f196e7e8; >= c4f75bc8bd6b3d62665e1f5400c419540edb5601, < 3b041514cb6eae45869b020f743c14d983363222 |
| Linux | Linux | 6.3 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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