SB20260720122 - Integer underflow in Linux kernel sw siw driver

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Main Vulnerability Database SB20260720122

SB20260720122 - Integer underflow in Linux kernel sw siw driver

Published: July 20, 2026

Security Bulletin ID SB20260720122
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-2026-64102)

CWE-ID: CWE-191 - Integer underflow

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to cause a denial of service and disclose kernel memory contents.

The vulnerability exists due to an integer underflow in the Soft-iWARP receive path (siw_get_hdr/siw_tcp_rx_data) when processing a malformed iWARP FPDU with an MPA length smaller than the fixed header length for the opcode. A remote user can send a specially crafted FPDU to cause a denial of service and disclose kernel memory contents.

The issue is triggered by a malicious connected siw peer, and the negative signed length is later promoted to size_t during skb_copy_bits processing.


Remediation

Install update from vendor's website.

References