VULNERABILITY INTELLIGENCE

CVE-2026-31662

CVSS score7.5 HIGH
EPSS probability0.39%
CISA KEVNot currently listed
Published2026-04-24
Last modified2026-10-19
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Weakness classification

  • nvd@nist.gov: CWE-191
  • 134c704f-9b21-4f2e-91b3-4a467353bcc0: CWE-190

Primary references