SB20261022150 - Integer underflow in Linux kernel core

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Main Vulnerability Database SB20261022150

SB20261022150 - Integer underflow in Linux kernel core

Published: October 22, 2026

Security Bulletin ID SB20261022150
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) Integer underflow (CVE-ID: CVE-2026-98573)

CWE-ID: CWE-191 - Integer underflow

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause memory corruption that may result in a denial of service.

The vulnerability exists due to an unsigned integer underflow in skb_maybe_pull_tail(), called by skb_checksum_setup_ipv6(), when parsing IPv6 extension headers. A remote attacker can supply crafted IPv6 packet data to trigger subtraction of skb_headlen(skb) from a smaller max value, producing a negative delta after conversion to a signed integer. This delta reaches skb_copy_bits() through __pskb_pull_tail(), where it can become a very large copy length and potentially cause memory corruption and a kernel crash.

The triggering condition requires an skb whose linear area exceeds MAX_IPV6_HDR_LEN and parsing that needs data beyond that linear area.


Remediation

Install update from vendor's website.

References