Skip to main content
VulnerabilityPublished Updated

CVE-2026-64298: Linux kernel · Missing Authorization

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in e36501b7d4abdcd6d69a7cb901b2f286b7a3d041 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in e36501b7d4abdcd6d69a7cb901b2f286b7a3d041, cb148a2762d644bff1894728e8835a9a4b84f9ea, a937e92c1d00534b5c2e3e9f4381b7e988180797 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ af22f94ae02ab9dd4fd7fe628c8434a59cc293be, < e36501b7d4abdcd6d69a7cb901b2f286b7a3d041
Fixed in
  • e36501b7d4abdcd6d69a7cb901b2f286b7a3d041
LinuxLinuxAffected
  • ≥ af22f94ae02ab9dd4fd7fe628c8434a59cc293be, < cb148a2762d644bff1894728e8835a9a4b84f9ea
Fixed in
  • cb148a2762d644bff1894728e8835a9a4b84f9ea
LinuxLinuxAffected
  • ≥ af22f94ae02ab9dd4fd7fe628c8434a59cc293be, < a937e92c1d00534b5c2e3e9f4381b7e988180797
Fixed in
  • a937e92c1d00534b5c2e3e9f4381b7e988180797
LinuxLinuxAffected
  • ≥ af22f94ae02ab9dd4fd7fe628c8434a59cc293be, < 5140f099ecd8a2f2808b7f7b720ee1bad8468974
Fixed in
  • 5140f099ecd8a2f2808b7f7b720ee1bad8468974
LinuxLinuxAffected
  • ≥ af22f94ae02ab9dd4fd7fe628c8434a59cc293be, < 4817c8974315b666e895b7d1bb83cd3664c323b1
Fixed in
  • 4817c8974315b666e895b7d1bb83cd3664c323b1
LinuxLinuxAffected
  • ≥ af22f94ae02ab9dd4fd7fe628c8434a59cc293be, < 30fdf4df6c3c00efec947e4ddf97f0fdd4473628
Fixed in
  • 30fdf4df6c3c00efec947e4ddf97f0fdd4473628

Description

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.

References

Community reviews

Loading reviews…