CVE-2026-31662
type: TechArticle
description: 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.
date published: 2026-04-24T15:16:45.820
license: https://creativecommons.org/publicdomain/zero/1.0/
source: https://nvd.nist.gov/vuln/detail/CVE-2026-31662
publisher: AI Analytics
source organization: NIST National Vulnerability Database
main entity: Thing
  additional type: Vulnerability
  score: 7.5
  severity: HIGH
keywords: CWE-191

AI Analytics
type: Organization