{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.1.5-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  net: lwtunnel: Drop skb metadata before LWT encapsulation  skb metadata is meant for passing information between XDP and TC. It lives in the skb headroom, immediately before skb-\u003edata. LWT programs cannot access the __sk_buff-\u003edata_meta pseudo-pointer to metadata.  However, LWT encapsulation prepends outer headers, moving skb-\u003edata back over the headroom where the metadata sits. On an RX-originated (forwarded) packet that still carries XDP metadata this goes wrong in two different ways, depending on the encap type:  1. Non-BPF LWT encaps (mpls, seg6, ioam6 ...) call skb_push()/skb_pull()    and silently overwrite the metadata that sits in the headroom.  2) BPF LWT xmit calls bpf_skb_change_head(), which uses skb_data_move().    That helper expects metadata immediately before skb-\u003edata. But since    the IP output path runs LWT xmit before neighbour output has built    the outgoing L2 header, for forwarded packets skb-\u003edata points at the    L3 header while skb_mac_header() still points at the old L2 header.    skb_data_move() sees metadata ending at skb_mac_header(), not before    skb-\u003edata, warns and clears metadata:    WARNING: CPU: 21 PID: 454557 at include/linux/skbuff.h:4609 skb_data_move+0x47/0x90   CPU: 21 UID: 0 PID: 454557 Comm: napi/iconduit-g Tainted: G           O        6.18.21 #1   RIP: 0010:skb_data_move+0x47/0x90   Call Trace:    \u003cIRQ\u003e    bpf_skb_change_head+0xe6/0x1a0    bpf_prog_...+0x213/0x2e3    run_lwt_bpf.isra.0+0x1d3/0x360    bpf_xmit+0x46/0xe0    lwtunnel_xmit+0xa1/0xf0    ip_finish_output2+0x1e7/0x5e0    ip_output+0x63/0x100    __netif_receive_skb_one_core+0x85/0xa0    process_backlog+0x9c/0x150    __napi_poll+0x2b/0x190    net_rx_action+0x40b/0x7f0    handle_softirqs+0xd2/0x270    do_softirq+0x3f/0x60    \u003c/IRQ\u003e  That is what happens, as for how to fix it - a received packet that carries metadata can reach an encap through any of the three LWT redirect modes:    LWTUNNEL_STATE_INPUT_REDIRECT    ip6_rcv_finish      dst_input        lwtunnel_input    LWTUNNEL_STATE_OUTPUT_REDIRECT    ip6_rcv_finish      dst_input        ip6_forward          ip6_forward_finish            dst_output              lwtunnel_output    LWTUNNEL_STATE_XMIT_REDIRECT    ip6_rcv_finish      dst_input        ip6_forward          ip6_forward_finish            dst_output              ip6_output                ip6_finish_output                  ip6_finish_output2                    lwtunnel_xmit  Every encap funnels through the three LWT dispatch helpers, so drop the metadata there, right before handing the skb to the encap op. This single chokepoint covers all encap types and all three redirect modes:    - lwtunnel_input():  seg6, rpl, ila, seg6_local   - lwtunnel_output(): ioam6   - lwtunnel_xmit():   mpls, LWT BPF xmit  Alternatively, we could clear the metadata right after TC ingress hook. That would require a compromise, however. Metadata would become inaccessible from TC egress (in setups where it actually reaches the hook it tact, that is without any L2 tunnels on path).",
  "id": "DEBIAN-CVE-2026-80612",
  "modified": "2026-09-14T16:47:31.566717268Z",
  "published": "2026-08-28T08:16:45.183Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-80612"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-80612"
  ]
}