CVE intelligence

CVE-2026-99031

Vulnerability intelligence

Published Oct 23, 2026Sources checked Oct 27, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-99031. 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 26, 2026

Release Notes

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-99031?

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

net: bridge: avoid recursive multicast port cleanup

br_multicast_sg_del_exclude_ports() removes automatically added STAR_EXCL port groups by calling br_multicast_del_pg(). For S,G entries, that deletion calls back into br_multicast_sg_del_exclude_ports(), so a large number of STAR_EXCL ports consumes one kernel stack frame per port and can hit the stack guard page.

Keep the complete port-group deletion path for cleanup, but suppress the S,G exclude-port cleanup while that helper is already walking the same entry. Normal deletion callers retain the existing behavior.

Source: NVD