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CVE-2026-98402

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

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 524c341cb16a8d5318d2ffacf6fe160271a18743 before ec6d4612d1c170e1cef1fe55526471da1e81e777; affected 21b28f97e621cba196fb32c576734d216a8a79c9 before 99654b651c6d5fe865798a2adb859767905f9278; affected db3efdcf70c752e8a8deb16071d8e693c3ef8746 before b972b5e6168dc5d1e13297b1f37f71d6b21cc0f1; affected db3efdcf70c752e8a8deb16071d8e693c3ef8746 before 04c0d35bac5122b533672a6775851dfae84e265e; affected db3efdcf70c752e8a8deb16071d8e693c3ef8746 before 2b32f8c3560905582fb12ed68315a6e606367a6a; affected db3efdcf70c752e8a8deb16071d8e693c3ef8746 before 7fcc2fe39fed1cb98a7374a113ff3800e8f9af80; affected 6.1.130 before 6.1.189; affected 6.6.81 before 6.6.158
Linux / Linuxaffected 6.10; unaffected 0 before 6.10; unaffected 6.1.189 through 6.1.*; unaffected 6.6.158 through 6.6.*; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References