SB20260816218 - Use-after-free in Linux kernel netfilter ipset

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Main Vulnerability Database SB20260816218

SB20260816218 - Use-after-free in Linux kernel netfilter ipset

Published: August 16, 2026

Security Bulletin ID SB20260816218
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use-after-free (CVE-ID: CVE-2026-74492)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to a use-after-free in mtype_add() when processing packet-side add operations during ipset table resizing. A remote user can trigger xt_SET --add-set ... --exist updates to cause a denial of service.

The issue occurs when a replacement-table entry and an old-table entry temporarily share the same comment pointer during resize and backlog replay, leading to a stale pointer dereference in strlen().


Remediation

Install update from vendor's website.

References