{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.111-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.2.7-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  net: iptunnel: fix stale transport header during tunnel decapsulation  Syzbot reported a crash in qdisc_pkt_len_segs_init() caused by a stale transport_header offset after tunnel decapsulation.  BUG: unable to handle page fault for address: ffffed102091a42e Oops: Oops: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 340 Comm: qdisc_uaf_repro Not tainted 7.2.0-rc4-00061-g248951ddc14d #256 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:__asan_load2 \u003cIRQ\u003e qdisc_pkt_len_segs_init (net/core/dev.c:4145) __dev_queue_xmit (net/core/dev.c:4787) br_dev_queue_push_xmit (net/bridge/br_forward.c:53) br_handle_frame_finish (net/bridge/br_input.c:229) br_handle_frame (net/bridge/br_input.c:315) __netif_receive_skb_core.constprop.0 (net/core/dev.c:6099) __netif_receive_skb_list_core (net/core/dev.c:6287) netif_receive_skb_list_internal (net/core/dev.c:6445) napi_complete_done (net/core/dev.c:6813) gro_cell_poll (net/core/gro_cells.c:74) __napi_poll (net/core/dev.c:7735) net_rx_action (net/core/dev.c:7798 net/core/dev.c:7955) handle_softirqs (kernel/softirq.c:622) do_softirq (kernel/softirq.c:523  kernel/softirq.c:510 ) __local_bh_enable_ip (kernel/softirq.c:450) tun_get_user (drivers/net/tun.c:1986 (discriminator 1)) tun_chr_write_iter (drivers/net/tun.c:2032)  The issue is completely latent until qdisc read transport header in commit 7fb4c1967011 (\"net: pull headers in qdisc_pkt_len_segs_init()\"). The crash requires four conditions to line up:  1. The incoming packet is encapsulated and carries GSO metadata. The outer    transport header offset is stored in skb-\u003etransport_header while the    packet is still in the outer tunnel context. 2. The tunnel receiver strips the outer headers. skb-\u003edata is advanced to    the inner frame, but skb-\u003etransport_header is left pointing to the    now-removed outer L4 header, so it becomes a negative offset relative to    the new data. 3. The inner frame is not delivered to the local IP stack. Instead, it    is forwarded at L2 by a bridge or HSR, so ip_rcv_core() never runs and    the transport header is not reset to the inner L4 offset. 4. The forwarding path calls __dev_queue_xmit(), which enters    qdisc_pkt_len_segs_init(). That function computes the GSO header length    from skb_transport_offset(skb). Because the offset is negative, the    unsigned cast overflows and pskb_may_pull(skb, hdr_len +    sizeof(struct tcphdr)) reads past the end of the skb, triggering a    KASAN fault or page fault.  The issue specifically requires GSO packets (shinfo-\u003egso_size != 0), which are processed/aggregated through gro_cells. Fix this by clearing transport_header to the ~0U sentinel in gro_cell for all tunnnel driver. GTP does not support GRO/GSO, drop the evil GSO packets in GTP directly.",
  "id": "DEBIAN-CVE-2026-98401",
  "modified": "2026-10-15T04:47:24.894423608Z",
  "published": "2026-10-14T14:17:51.120Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-98401"
    }
  ],
  "upstream": [
    "CVE-2026-98401"
  ]
}