CVE-2026-74480: Linux

Critical severity, CVSS 9.8. EPSS: 0.6% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net: bridge: stop fast-leave after deleting a port group br_multicast_leave_group() iterates mp->ports with pp = &p->next in its fast-leave path. After br_multicast_del_pg() removes p, continuing the loop advances pp through the deleted entry. If multicast-to-unicast was enabled, the bridge can hold multiple port groups for the same port and group with different source MAC addresses. Once multicast-to-unicast is disabled, br_port_group_equal() matches those entries by port only. A fast leave can then delete one entry and continue from its stale next pointer, leaving mp->ports pointing at a deleted port group. Fast leave only needs to remove one matching port group. Break after br_multicast_del_pg() so the loop stops before dereferencing the removed entry.

Affected products

• Linux Linux: from 4.11, before 5.10.265 (fixed in 5.10.265); from 5.11, before 5.15.216 (fixed in 5.15.216); from 5.16, before 6.1.183 (fixed in 6.1.183); from 6.2, before 6.6.151 (fixed in 6.6.151); from 6.7, before 6.12.103 (fixed in 6.12.103); from 6.13, before 6.18.44 (fixed in 6.18.44); …

Published 2026-08-15. Last modified 2026-08-19.