memfd: deny writeable mappings when implying SEAL_WRITE
Priority LOW 37CWE-362Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00127 2nd percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.6.143, 6.12.93, 6.18.35 +2Red Hat: 4 advisories
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.3 and later | 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1 | Patch available | CNA |
- Linux VendorLinux Affected 6.3 and later Fixed in 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.3 to before 6.6.143; 6.7 to before 6.12.93; 6.13 to before 6.18.35; 6.19 to before 7.0.12 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | 7.1 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* | 7.1 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* | 7.1 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* | 7.1 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* | 7.1 rc5 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.3 to before 6.6.143; 6.7 to before 6.12.93; 6.13 to before 6.18.35; 6.19 to before 7.0.12 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* Versions 7.1 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* Versions 7.1 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* Versions 7.1 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* Versions 7.1 rc5 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1
Red Hat 4 advisories
- RHSA-2026:69089 Released 2026-09-21 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.105.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.105.1.el10_0, kernel-64k-devel-6.12.0-55.105.1.el10_0 +12
- Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.105.1.el10_0, kernel-64k-6.12.0-55.105.1.el10_0, kernel-64k-core-6.12.0-55.105.1.el10_0 +28
- Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.105.1.el10_0, libperf-6.12.0-55.105.1.el10_0
- Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.105.1.el10_0, kernel-rt-64k-6.12.0-55.105.1.el10_0, kernel-rt-64k-core-6.12.0-55.105.1.el10_0 +21
- Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.105.1.el10_0, kernel-rt-core-6.12.0-55.105.1.el10_0, kernel-rt-debug-6.12.0-55.105.1.el10_0 +11
- RHSA-2026:67720 Released 2026-09-16 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.141.1.el9_6, libperf-5.14.0-570.141.1.el9_6
- Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.141.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.141.1.el9_6, kernel-64k-devel-5.14.0-570.141.1.el9_6 +12
- Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.141.1.el9_6, kernel-64k-5.14.0-570.141.1.el9_6, kernel-64k-core-5.14.0-570.141.1.el9_6 +28
- Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.141.1.el9_6, kernel-rt-64k-5.14.0-570.141.1.el9_6, kernel-rt-64k-core-5.14.0-570.141.1.el9_6 +21
- Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.141.1.el9_6, kernel-rt-core-5.14.0-570.141.1.el9_6, kernel-rt-debug-5.14.0-570.141.1.el9_6 +11
- RHSA-2026:57252 Released 2026-08-20 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.41.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.41.1.el9_8, kernel-64k-devel-5.14.0-687.41.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.41.1.el9_8, kernel-64k-5.14.0-687.41.1.el9_8, kernel-64k-core-5.14.0-687.41.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.41.1.el9_8, libperf-5.14.0-687.41.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-64k-5.14.0-687.41.1.el9_8, kernel-rt-64k-core-5.14.0-687.41.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-core-5.14.0-687.41.1.el9_8, kernel-rt-debug-5.14.0-687.41.1.el9_8 +9
Show 1 more Red Hat advisories
- RHSA-2026:57251 Released 2026-08-20 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.49.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.49.1.el10_2, kernel-64k-devel-6.12.0-211.49.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.49.1.el10_2, kernel-64k-6.12.0-211.49.1.el10_2, kernel-64k-core-6.12.0-211.49.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.49.1.el10_2, libperf-6.12.0-211.49.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.49.1.el10_2, kernel-rt-64k-6.12.0-211.49.1.el10_2, kernel-rt-64k-core-6.12.0-211.49.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.49.1.el10_2, kernel-rt-core-6.12.0-211.49.1.el10_2, kernel-rt-debug-6.12.0-211.49.1.el10_2 +9
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat CodeReady Linux Builder EUS (v.9.6) | Fixed | RHSA-2026:67720 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:57251 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:57252 |
| Red Hat Enterprise Linux AppStream EUS (v. 10.0) | Fixed | RHSA-2026:69089 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:67720 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:57251 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:57252 |
| Red Hat Enterprise Linux BaseOS EUS (v. 10.0) | Fixed | RHSA-2026:69089 |
| Red Hat Enterprise Linux BaseOS EUS (v.9.6) | Fixed | RHSA-2026:67720 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:57251 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:57252 |
| Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) | Fixed | RHSA-2026:69089 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:57251 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:57252 |
| Red Hat Enterprise Linux Real Time EUS (v. 10.0) | Fixed | RHSA-2026:69089 |
| Red Hat Enterprise Linux Real Time EUS (v.9.6) | Fixed | RHSA-2026:67720 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:57251 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:57252 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) | Fixed | RHSA-2026:69089 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) | Fixed | RHSA-2026:67720 |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-63952
- 2026-10-03 Alias added: GHSA-6pc4-h32v-99rg
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-19 Weakness changed · CISA ADP
- 2026-10-29 Affected versions changed · Red Hat
References
Patch 5
- https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e
- https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4
- https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08
- https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8
- https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222
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Sources
- CVE-2026-63952 · CVE Program
- CVE-2026-63952 · NVD
- FIRST EPSS
- GHSA-6pc4-h32v-99rg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-63952 · Red Hat security data · CC BY 4.0
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