CVE intelligence

CVE-2026-89476

Vulnerability intelligence

Published Sep 11, 2026Sources checked Oct 30, 2026

7.5HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-89476 and is rated High severity with a CVSS score of 7.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 2, 2026

Release Notes

Vendor-listed releases

6.6.157.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.7%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-89476?

In the Linux kernel, the following vulnerability has been resolved:

sctp: fix stream->outcnt underflow on duplicate RECONF responses

A cached RECONF chunk may contain more than one request parameter. A duplicate response can therefore find and process the same ADD_OUT request again while another parameter is still outstanding, rolling back outcnt twice and possibly underflowing it.

Track outstanding request types as bits and clear each bit after its first response. Later responses for the same request are then ignored.

Source: NVD