SB20260720440 - Improper access control in Linux kernel tls

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Main Vulnerability Database SB20260720440

SB20260720440 - Improper access control in Linux kernel tls

Published: July 20, 2026

Security Bulletin ID SB20260720440
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-2026-63830)

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 modify the page cache contents.

The vulnerability exists due to improper access control in the sk_msg scatter-gather handling logic when processing SK_MSG transformations and BPF message helpers. A local user can trigger scatterlist entry transfers, shifts, splits, or copies that desynchronize sg.copy state to modify the page cache contents.

Exploitation requires the ability to reach a later SK_MSG verdict that exposes sg_virt(sge) as writable BPF ctx->data.


Remediation

Install update from vendor's website.

References