Answer in brief
CVE-2026-31662 records a High severity (CVSS 7.5) vulnerability in tipc: fix bc_ackers underflow on duplicate GRP_ACK_MSG. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=2f487712b89376fce267223bbb0db93d393d4b09 <a7db57ccca21f5801609065473c89a38229ecb92 || >=2f487712b89376fce267223bbb0db93d393d4b09 <36ec4fdd6250dcd5e73eb09ea92ed92e9cc28412 || >=2f487712b89376fce267223bbb0db93d393d4b09 <575faea557f1a184a5f09661bd47ebd3ef3769f8 || >=2f487712b89376fce267223bbb0db93d393d4b09 <3bcf7aca63f0bcd679ae28e9b99823c608e59ce3 || >=2f487712b89376fce267223bbb0db93d393d4b09 <a2ea1ef0167d7a84730638d05c20ccdc421b14b6 || >=2f487712b89376fce267223bbb0db93d393d4b09 <1b6f13f626665cac67ba5a012765427680518711 || >=2f487712b89376fce267223bbb0db93d393d4b09 <e0bb732eaf77f9ac2f2638bdac9e39b81e0a9682 || >=2f487712b89376fce267223bbb0db93d393d4b09 <48a5fe38772b6f039522469ee6131a67838221a8 | a7db57ccca21f5801609065473c89a38229ecb92, 36ec4fdd6250dcd5e73eb09ea92ed92e9cc28412, 575faea557f1a184a5f09661bd47ebd3ef3769f8, 3bcf7aca63f0bcd679ae28e9b99823c608e59ce3, a2ea1ef0167d7a84730638d05c20ccdc421b14b6, 1b6f13f626665cac67ba5a012765427680518711, e0bb732eaf77f9ac2f2638bdac9e39b81e0a9682, 48a5fe38772b6f039522469ee6131a67838221a8 |
| Linux/Linuxgeneric | 4.15 | Not reported |
Published upstream
Apr 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 16, 2026
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.
Quoted source text, attributed separately from HOL analysis.