SB20261007108 - Improper input validation in Linux kernel ipv4

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Main Vulnerability Database SB20261007108

SB20261007108 - Improper input validation in Linux kernel ipv4

Published: October 7, 2026

Security Bulletin ID SB20261007108
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper input validation (CVE-ID: CVE-2026-98255)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to improperly modify TCP connection state.

The vulnerability exists due to improper acknowledgment validation in the TCP receive fast path of tcp_rcv_established() when processing segments with acknowledgment sequence numbers before SND.UNA. A remote attacker can send a TCP segment carrying payload and an excessively old acknowledgment to improperly modify TCP connection state.

The segment's sequence number must match RCV.NXT, and its TCP flags must match the fast-path prediction flags.


Remediation

Install update from vendor's website.

References