Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 4.15.1, < 5.10.253 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/1b6f13f626665cac67ba5a012765427680518711Patch
- https://git.kernel.org/stable/c/36ec4fdd6250dcd5e73eb09ea92ed92e9cc28412Patch
- https://git.kernel.org/stable/c/3bcf7aca63f0bcd679ae28e9b99823c608e59ce3Patch
- https://git.kernel.org/stable/c/48a5fe38772b6f039522469ee6131a67838221a8Patch
- https://git.kernel.org/stable/c/575faea557f1a184a5f09661bd47ebd3ef3769f8Patch
- https://git.kernel.org/stable/c/a2ea1ef0167d7a84730638d05c20ccdc421b14b6Patch
- https://git.kernel.org/stable/c/a7db57ccca21f5801609065473c89a38229ecb92Patch
- https://git.kernel.org/stable/c/e0bb732eaf77f9ac2f2638bdac9e39b81e0a9682Patch
FAQ
What is CVE-2026-31662?
CVE-2026-31662 is a vulnerability with a CVSS score of 7.5 (HIGH). 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_a...
How severe is CVE-2026-31662?
CVE-2026-31662 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-31662?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.