SB20260720226 - Integer underflow in Linux kernel xfrm

CSH
CYBERSECURITY HELP
Sign In REGISTER

Main Vulnerability Database SB20260720226

SB20260720226 - Integer underflow in Linux kernel xfrm

Published: July 20, 2026

Security Bulletin ID SB20260720226
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Integer underflow (CVE-ID: CVE-2026-64009)

CWE-ID: CWE-191 - Integer underflow

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


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

The vulnerability exists due to an integer underflow leading to an out-of-bounds write in the esp component, specifically xfrm_state_mtu(), when processing a UDP datagram through an IPv4 ESP tunnel SA with attacker-controlled parameters. A local user can install a crafted IPv4 ESP tunnel SA and send a UDP datagram through the tunnel to cause a denial of service.

The issue involves a negative length being sign-extended to size_t before being passed to memset() in esp_output_fill_trailer().


Remediation

Install update from vendor's website.

References