NFSv4: include MAY_WRITE in open permission mask for O_TRUNC
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.
CVE-2026-64298
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64298
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "4817c8974315b666e895b7d1bb83cd3664c323b1",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "cb148a2762d644bff1894728e8835a9a4b84f9ea",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "30fdf4df6c3c00efec947e4ddf97f0fdd4473628",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "22c1fd1355ad4ca27aa7f0fa02719122dd92d9de",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "a937e92c1d00534b5c2e3e9f4381b7e988180797",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "e36501b7d4abdcd6d69a7cb901b2f286b7a3d041",
"versionType": "git"
},
{
"status": "affected",
"version": "af22f94ae02ab9dd4fd7fe628c8434a59cc293be",
"lessThan": "5140f099ecd8a2f2808b7f7b720ee1bad8468974",
"versionType": "git"
}
],
"programFiles": [
"fs/nfs/dir.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.24"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.24",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfs/dir.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64298
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40999 · Revision 1
- Added to Heist Feed
- Publisher date