SB20260720289 - Improper access control in Linux kernel mm

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Main Vulnerability Database SB20260720289

SB20260720289 - Improper access control in Linux kernel mm

Published: July 20, 2026

Security Bulletin ID SB20260720289
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-2026-63952)

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 write sealing protections and modify a memfd that appears to be write sealed.

The vulnerability exists due to improper access control in memfd_add_seals() in mm/memfd.c when adding SEAL_EXEC to a memfd with writable mappings. A local user can add a seal combination that implies SEAL_WRITE after the writable-mapping check to bypass write sealing protections and modify a memfd that appears to be write sealed.

The issue occurs because SEAL_EXEC implies SEAL_WRITE, but the implied seal was applied only after the check for writable mappings.


Remediation

Install update from vendor's website.

References