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Review reviewHigh

CVE-2026-64298

Linux

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...

CVSS
7.1
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.25
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.1

Vulnerability overview

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...

Affected product and versions

Product
Linux
Affected versions
>= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < 4817c8974315b666e895b7d1bb83cd3664c323b1, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < cb148a2762d644bff1894728e8835a9a4b84f9ea, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < 30fdf4df6c3c00efec947e4ddf97f0fdd4473628, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < 22c1fd1355ad4ca27aa7f0fa02719122dd92d9de, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < 6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < a937e92c1d00534b5c2e3e9f4381b7e988180797, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < e36501b7d4abdcd6d69a7cb901b2f286b7a3d041, >= af22f94ae02ab9dd4fd7fe628c8434a59cc293be < 5140f099ecd8a2f2808b7f7b720ee1bad8468974, >= 2.6.24
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CWE
Not available
CVE-2026-64298 — Linux | SECUFOCUS NOW