SB20260720438 - Improper access control in Linux kernel apparmor

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Main Vulnerability Database SB20260720438

SB20260720438 - Improper access control in Linux kernel apparmor

Published: July 20, 2026

Security Bulletin ID SB20260720438
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-2026-63828)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to bypass AppArmor connect restrictions.

The vulnerability exists due to improper access control in apparmor_socket_sendmsg() when processing sendmsg()/sendto() calls with MSG_FASTOPEN and a supplied destination address. A local user can send a crafted fast open request to bypass AppArmor connect restrictions.

The issue affects implicit TCP and MPTCP connection establishment performed as part of sendmsg() fast open handling.


Remediation

Install update from vendor's website.

References