---
id: CVE-2026-98402
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: icmp: avoid invalid transport header access in icmp_send tracepoint

  syzbot reported a WARNING triggered by DEBUG_NET_WARN_ON_ONCE():

   WARNING: at skb_transport_h…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: icmp: avoid invalid transport header access in icmp_send tracepoint

  syzbot reported a WARNING triggered by DEBUG_NET_WARN_ON_ONCE():

   WARNING: at skb_transport_h…
severity: none
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T14:17:51.257'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98402'
references:
  - url: 'https://git.kernel.org/stable/c/04c0d35bac5122b533672a6775851dfae84e265e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2b32f8c3560905582fb12ed68315a6e606367a6a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7fcc2fe39fed1cb98a7374a113ff3800e8f9af80'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/99654b651c6d5fe865798a2adb859767905f9278'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b972b5e6168dc5d1e13297b1f37f71d6b21cc0f1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ec6d4612d1c170e1cef1fe55526471da1e81e777'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
ingestedAt: '2026-10-14T15:36:13.981Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

net: icmp: avoid invalid transport header access in icmp_send tracepoint

syzbot reported a WARNING triggered by DEBUG_NET_WARN_ON_ONCE():

 WARNING: at skb_transport_header include/linux/skbuff.h:3087 [inline]
 WARNING: at udp_hdr include/linux/udp.h:23 [inline]
 WARNING: at do_trace_event_raw_event_icmp_send include/trace/events/icmp.h:30 [inline]
 WARNING: at trace_event_raw_event_icmp_send+0x48c/0x6ec include/trace/events/icmp.h:11
 Call trace:
  skb_transport_header include/linux/skbuff.h:3087 [inline]
  udp_hdr include/linux/udp.h:23 [inline]
  do_trace_event_raw_event_icmp_send include/trace/events/icmp.h:30 [inline]
  trace_event_raw_event_icmp_send+0x48c/0x6ec include/trace/events/icmp.h:11
  __traceiter_icmp_send include/trace/events/icmp.h:11 [inline]
  __do_trace_icmp_send include/trace/events/icmp.h:11 [inline]
  trace_icmp_send+0x320/0x49c include/trace/events/icmp.h:11
  __icmp_send+0xcfc/0x11d8 net/ipv4/icmp.c:1013
  ipv4_send_dest_unreach net/ipv4/route.c:1280 [inline]
  ipv4_link_failure+0x57c/0x8dc net/ipv4/route.c:1287
  dst_link_failure include/net/dst.h:438 [inline]
  vti_tunnel_xmit+0xe40/0x17a4 net/ipv4/ip_vti.c:307

TP_fast_assign() unconditionally calls udp_hdr(skb) before checking
whether the packet is UDP. Furthermore, __icmp_send() can be invoked
from paths (e.g., link failures, ARP errors, forwarding, AF_PACKET)
where skb->transport_header was never initialized (~0U).

Under CONFIG_DEBUG_NET=y, calling skb_transport_header(skb) triggers
DEBUG_NET_WARN_ON_ONCE(!skb_transport_header_was_set(skb)).

Fix this by:
1. Only parsing transport info when iph->protocol == IPPROTO_UDP.
2. Using skb_header_pointer() at skb_network_offset(skb) + (iph->ihl << 2)
   to safely fetch the UDP header without assuming transport_header is set.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.