SB20261023113 - Protection mechanism failure in Linux kernel selinux

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Main Vulnerability Database SB20261023113

SB20261023113 - Protection mechanism failure in Linux kernel selinux

Published: October 23, 2026

Security Bulletin ID SB20261023113
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) Protection mechanism failure (CVE-ID: CVE-2026-99052)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local privileged user to disable SELinux per-file security labeling on shared NFSv4 mounts.

The vulnerability exists due to failure to preserve the SECURITY_LSM_NATIVE_LABELS flag in selinux_set_mnt_opts() when an already-initialized superblock is reused for a second mount. A local privileged user can trigger a second mount of an NFSv4 filesystem exported with security_label to cause nfs_get_root() to clear NFS_CAP_SECURITY_LABEL on the shared nfs_server, disabling per-file labeling for both the original and new mounts.


Remediation

Install update from vendor's website.

References