CVE-2026-31662

A flaw was found in the Linux kernel's Transparent Inter-Process Communication (TIPC) protocol. An attacker can exploit an integer underflow vulnerability by sending duplicate group acknowledgment messages (GRP_ACK_MSG). This causes the bc_ackers counter to wrap around, leading to persistent network congestion. Consequently, group broadcasts on the affected socket become blocked, resulting in a denial of service until the group is manually recreated.

Duplicate TIPC group ACKs could decrement bc_ackers below zero; upstream guards the path. Red Hat recommends patched kernels on TIPC clusters; unload tipc where the protocol is unused.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the tipc module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.