CVE-2026-64298 (GCVE-0-2026-64298)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-07-27 04:59
VLAI
Title
NFSv4: include MAY_WRITE in open permission mask for O_TRUNC
Summary
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.
Assigner
Impacted products
Vendor Product Version
Linux Linux Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < 4817c8974315b666e895b7d1bb83cd3664c323b1 (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < cb148a2762d644bff1894728e8835a9a4b84f9ea (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < 30fdf4df6c3c00efec947e4ddf97f0fdd4473628 (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < 22c1fd1355ad4ca27aa7f0fa02719122dd92d9de (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < 6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230 (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < a937e92c1d00534b5c2e3e9f4381b7e988180797 (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < e36501b7d4abdcd6d69a7cb901b2f286b7a3d041 (git)
Affected: af22f94ae02ab9dd4fd7fe628c8434a59cc293be , < 5140f099ecd8a2f2808b7f7b720ee1bad8468974 (git)
Create a notification for this product.
Linux Linux Affected: 2.6.24
Unaffected: 0 , < 2.6.24 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.96 , ≤ 6.12.* (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc3 , ≤ * (original_commit_for_fix)
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Show details on NVD website

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    "dateReserved": "2026-07-19T15:36:31.778Z",
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    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-07-25T16:46:17Z",
      "cve": "CVE-2026-64298",
      "id": "CVE-2026-64298",
      "initial_release_date": "2026-07-25T16:46:17Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64298",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64298.json",
      "version": "2"
    }
  }
}



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