SB20260727282 - Improper access control in Linux kernel nfs

CSH
CYBERSECURITY HELP
Sign In REGISTER

Main Vulnerability Database SB20260727282

SB20260727282 - Improper access control in Linux kernel nfs

Published: July 27, 2026

Security Bulletin ID SB20260727282
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Data manipulation

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper access control (CVE-ID: CVE-2026-64298)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to bypass file write permission checks and truncate a file.

The vulnerability exists due to improper access control in nfs_open_permission_mask() when handling open requests with O_TRUNC on NFSv4 delegated opens. A local user can open a file with O_RDONLY | O_TRUNC to bypass file write permission checks and truncate a file.

This issue occurs when the client satisfies the OPEN locally from a cached write delegation and then sends truncation to the server using delegation state.


Remediation

Install update from vendor's website.

References