SB20260917187 - Out-of-bounds write in Linux kernel ipv6



SB20260917187 - Out-of-bounds write in Linux kernel ipv6

Published: September 17, 2026

Security Bulletin ID SB20260917187
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Out-of-bounds write (CVE-ID: CVE-2026-89783)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to compromise confidentiality, integrity, and availability.

The vulnerability exists due to an out-of-bounds write in xfrm6_input_addr() when processing an inner IPv6 packet containing a destination-options HAO option or a type-2 routing header. A remote attacker can send a specially crafted packet to compromise confidentiality, integrity, and availability.

Exploitation requires the transport-mode receive path to re-enter IPv6 input with a secpath whose length is at the maximum depth.


Remediation

Install update from vendor's website.