memfd: deny writeable mappings when implying SEAL_WRITE
Summary
| CVE | CVE-2026-63952 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-19 16:17:13 UTC |
| Updated | 2026-07-20 15:16:58 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 8.4 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 8.4 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
| 3.1 | CNA | DECLARED | 8.4 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
ChangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 b3f4f82d1315f1439059a83d1c22c51a5b43d99e git | Not specified |
| CNA | Linux | Linux | affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 3be2a24f7f72ad7321ed6ad1715b956a4527bcf4 git | Not specified |
| CNA | Linux | Linux | affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 0995d1f79aed8ccbf62056189dd53fd19726ea08 git | Not specified |
| CNA | Linux | Linux | affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 555702282d4536a865dfffb1cd4f6028f196e7e8 git | Not specified |
| CNA | Linux | Linux | affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 3b041514cb6eae45869b020f743c14d983363222 git | Not specified |
| CNA | Linux | Linux | affected 6.3 | Not specified |
| CNA | Linux | Linux | unaffected 6.3 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.143 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.93 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.35 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0.12 7.0.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.