Tracker / CVE-2026-31662
CVE-2026-31662
In the Linux kernel, the following vulnerability has been resolved: tipc: fix bc_ackers underflow on duplicate GRP_ACK_MSG The GRP_ACK_MSG handler in tipc_group_proto_rcv() currently decrements bc_ackers on every inbound group ACK, even when the same member has already acknowledged the current broadcast round. Because bc_ackers is a u16, a duplicate ACK received after the last legitimate ACK wraps the counter to 65535. Once wrapped, tipc_group_bc_cong() keeps reporting congestion and later group broadcasts on the affected socket stay blocked until the group is recreated. Fix this by ignoring duplicate or stale ACKs before touching bc_acked or bc_ackers. This makes repeated GRP_ACK_MSG handling idempotent and prevents the underflow path.
Affected products and versions
| linux | linux_kernel |
|---|---|
| linux | linux_kernel · 4.15.1 → 5.10.253 |
| linux | linux_kernel · 5.11 → 5.15.203 |
| linux | linux_kernel · 5.16 → 6.1.169 |
| linux | linux_kernel · 6.13 → 6.18.23 |
| linux | linux_kernel · 6.19 → 6.19.13 |
| linux | linux_kernel · 6.2 → 6.6.135 |
| linux | linux_kernel · 6.7 → 6.12.82 |