SB20260626115 - Use of uninitialized resource in Linux kernel netfilter



SB20260626115 - Use of uninitialized resource in Linux kernel netfilter

Published: June 26, 2026

Security Bulletin ID SB20260626115
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Information disclosure

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use of uninitialized resource (CVE-ID: CVE-2026-53218)

CWE-ID: CWE-908 - Use of Uninitialized Resource

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to an uninitialized memory exposure in nft_exthdr_init and the nft_exthdr evaluation paths when processing a userspace request with the NFT_EXTHDR_F_PRESENT flag set and an invalid length value. A local user can supply a crafted netfilter expression that causes uninitialized stack data from nft_regs to be retained in registers and disclose sensitive information.

The issue occurs because the initialized register bitmap can mark more bytes as written than the evaluation paths actually store when the presence flag is used.


Remediation

Install update from vendor's website.