Answer in brief
CVE-2026-89564 records a Unknown severity vulnerability in ip: orphan prefetched skbs before multicast forwarding. 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.
A CVSS score is not reported in the current record. 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 | >=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce || >=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <f1281d4b99089fbaf0d3579bba62a814ebb4de4d || >=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <e36ce6e78fe3fc3c071a26750783b7ba081ce10d | a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce, f1281d4b99089fbaf0d3579bba62a814ebb4de4d, e36ce6e78fe3fc3c071a26750783b7ba081ce10d |
| Linux/Linuxgeneric | 5.7 | Not reported |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 11, 2026
In the Linux kernel, the following vulnerability has been resolved: ip: orphan prefetched skbs before multicast forwarding IPv4 and IPv6 input preserve an skb->sk association installed by bpf_sk_assign() so that local delivery can use the selected socket under RCU. Both address families can also prefetch a socket in UDP early demux. In both paths (BPF and UDP early demux) a reference is not guaranteed to be held on the socket. When a multicast packet is not locally deliverable, IPv6 hands the original skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the original skb when local delivery is not needed. Either path can put the skb on an unresolved multicast route queue or forward it after the receive-side RCU section ends. After the prefetched socket is destroyed, a later skb free invokes sock_pfree() and dereferences the stale skb->sk. Orphan the skb before each non-local multicast forwarding path. Local delivery retains the original skb; the existing skb_clone() calls provide multicast forwarding with a socket-free clone.
Quoted source text, attributed separately from HOL analysis.