Answer in brief
CVE-2026-63952 records a High severity (CVSS 8.4) vulnerability in memfd: deny writeable mappings when implying SEAL_WRITE. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=c4f75bc8bd6b3d62665e1f5400c419540edb5601 <b3f4f82d1315f1439059a83d1c22c51a5b43d99e || >=c4f75bc8bd6b3d62665e1f5400c419540edb5601 <3be2a24f7f72ad7321ed6ad1715b956a4527bcf4 || >=c4f75bc8bd6b3d62665e1f5400c419540edb5601 <0995d1f79aed8ccbf62056189dd53fd19726ea08 || >=c4f75bc8bd6b3d62665e1f5400c419540edb5601 <555702282d4536a865dfffb1cd4f6028f196e7e8 || >=c4f75bc8bd6b3d62665e1f5400c419540edb5601 <3b041514cb6eae45869b020f743c14d983363222 | b3f4f82d1315f1439059a83d1c22c51a5b43d99e, 3be2a24f7f72ad7321ed6ad1715b956a4527bcf4, 0995d1f79aed8ccbf62056189dd53fd19726ea08, 555702282d4536a865dfffb1cd4f6028f196e7e8, 3b041514cb6eae45869b020f743c14d983363222 |
| Linux/Linuxgeneric | 6.3 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.