CVE-2026-64298

CVE CVE-2026-64298EUVD EUVD-2026-49010Published 2026-07-25T08:49:35.000ZLast changed 2026-08-05T12:40:41.000ZCVSS 7.1

What the advisory describes

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.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux af22f94ae02ab9dd4fd7fe628c8434a59cc293be <4817c8974315b666e895b7d1bb83cd3664c323b1; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <5140f099ecd8a2f2808b7f7b720ee1bad8468974; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230; patch: 6.6.145; patch: 6.1.178; patch: 7.1.4; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <a937e92c1d00534b5c2e3e9f4381b7e988180797; patch: 0; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <22c1fd1355ad4ca27aa7f0fa02719122dd92d9de; 2.6.24; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <30fdf4df6c3c00efec947e4ddf97f0fdd4473628; patch: 5.15.212; patch: 7.2-rc3; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <cb148a2762d644bff1894728e8835a9a4b84f9ea; af22f94ae02ab9dd4fd7fe628c8434a59cc293be <e36501b7d4abdcd6d69a7cb901b2f286b7a3d041; patch: 6.12.96; patch: 6.18.39; patch: 5.10.261

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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