Answer in brief
CVE-2026-64298 records a High severity (CVSS 7.1) vulnerability in NFSv4: include MAY_WRITE in open permission mask for O_TRUNC. 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 7.1. 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:7.2:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <4817c8974315b666e895b7d1bb83cd3664c323b1 || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <cb148a2762d644bff1894728e8835a9a4b84f9ea || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <30fdf4df6c3c00efec947e4ddf97f0fdd4473628 || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <22c1fd1355ad4ca27aa7f0fa02719122dd92d9de || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230 || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <a937e92c1d00534b5c2e3e9f4381b7e988180797 || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <e36501b7d4abdcd6d69a7cb901b2f286b7a3d041 || >=af22f94ae02ab9dd4fd7fe628c8434a59cc293be <5140f099ecd8a2f2808b7f7b720ee1bad8468974 | 4817c8974315b666e895b7d1bb83cd3664c323b1, cb148a2762d644bff1894728e8835a9a4b84f9ea, 30fdf4df6c3c00efec947e4ddf97f0fdd4473628, 22c1fd1355ad4ca27aa7f0fa02719122dd92d9de, 6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230, a937e92c1d00534b5c2e3e9f4381b7e988180797, e36501b7d4abdcd6d69a7cb901b2f286b7a3d041, 5140f099ecd8a2f2808b7f7b720ee1bad8468974 |
| Linux/Linuxgeneric | 2.6.24 | Not reported |
Published upstream
Jul 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 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: NFSv4: include MAY_WRITE in open permission mask for O_TRUNC POSIX requires write permission to truncate a file, so an open() that specifies O_TRUNC must be authorized for write access regardless of the O_ACCMODE access mode. nfs_open_permission_mask() builds the access mask passed to nfs_may_open(), which is the local authorization gate for OPENs the client serves itself from a cached write delegation via the can_open_delegated() path in nfs4_try_open_cached(). The mask is derived from O_ACCMODE alone, so an open(O_RDONLY | O_TRUNC) against a file the caller cannot write requests only MAY_READ and passes the local check. The OPEN is then satisfied locally and the truncation is issued to the server as a SETATTR(size=0) over the delegation stateid, which the server accepts under standard write-delegation semantics. POSIX requires that this open fail with EACCES. Include MAY_WRITE in the mask whenever O_TRUNC is set so the local check matches the access the server would have enforced.
Quoted source text, attributed separately from HOL analysis.