CVE-2026-74480
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel, the bridge module has a bug in br_multicast_leave_group() that can lead to a use-after-free after deleting a port group during fast-leave multicast handling.
Risk Assessment
This vulnerability could cause a system crash or potential code execution by an attacker in kernel context, posing a serious threat to system integrity.
Recommendation
Apply the Linux kernel patch that breaks the loop after deleting the port group to avoid dereferencing the removed entry.
Original NVD description (English source)
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.