Answer in brief
CVE-2026-63952 records a Unknown severity 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.
A CVSS score is not reported in the current record. 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.
| 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
Aug 5, 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.
Answer in brief
CVE-2026-63952 records a Unknown severity 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.
A CVSS score is not reported in the current record. 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.
| 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
Aug 5, 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.