Answer in brief
CVE-2026-99041 records a Unknown severity vulnerability in ip6_gre: remove obsolete ERSPAN PMTU update. 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 | >=5a963eb61b7c39e6c422b6e48619d19d04719358 <b14a682ad7d45345701e08f9279d483a1da8b36c || >=5a963eb61b7c39e6c422b6e48619d19d04719358 <f5b143f4cd3fb7673df8d727550478a4b762908a || >=5a963eb61b7c39e6c422b6e48619d19d04719358 <2d06cb25a497d3a7034ef9d172626c2d6620a0f1 || >=5a963eb61b7c39e6c422b6e48619d19d04719358 <8f27260b989f488760289276377db24fbfb20bfa || >=5a963eb61b7c39e6c422b6e48619d19d04719358 <8bc60db48e8cba35488bbd6e1f94aa990afa275a | b14a682ad7d45345701e08f9279d483a1da8b36c, f5b143f4cd3fb7673df8d727550478a4b762908a, 2d06cb25a497d3a7034ef9d172626c2d6620a0f1, 8f27260b989f488760289276377db24fbfb20bfa, 8bc60db48e8cba35488bbd6e1f94aa990afa275a |
| Linux/Linuxgeneric | 4.16 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
In the Linux kernel, the following vulnerability has been resolved: ip6_gre: remove obsolete ERSPAN PMTU update A tc tunnel_key action can attach a METADATA_IP_TUNNEL dst to an skb, and mirred can redirect it to a native ip6erspan device. The legacy PMTU update in ip6erspan_tunnel_xmit() treats that metadata dst as a route. Since it has no output device, dst_dev(dst)->mtu dereferences NULL. On v7.2 with KASAN, an initial UID/GID 65534 process with CapEff 0 used self-created user and network namespaces to trigger: KASAN: null-ptr-deref RIP: ip6erspan_tunnel_xmit+0x10fc/0x2cc0 Kernel panic - not syncing: Fatal exception in interrupt The update is obsolete. Commit fe1a4ca0a2b7 ("ip6_gre: process toobig in a better way") changed IPv6 GRE Too Big handling to update the underlay route and removed the equivalent block from __gre6_xmit(). ip6_tnl_xmit() then propagates the underlay PMTU to the overlay route. Remove the stale ERSPAN copy and its now-unused dst variable. This eliminates the metadata-dst dereference and keeps ERSPAN aligned with IPv6 GRE PMTU handling.
Quoted source text, attributed separately from HOL analysis.