CVE-2026-64577
Description
In the Linux kernel, the following vulnerability has been resolved: gtp: check skb_pull_data() return in gtp1u_send_echo_resp() gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr + gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For a 16-19 byte echo request the pull fails and returns NULL without advancing skb->data; execution continues, and the following skb_push() plus the IP header pushed by iptunnel_xmit() move skb->data below skb->head, tripping skb_under_panic(). Fix it by dropping the packet when skb_pull_data() fails. skbuff: skb_under_panic: ... kernel BUG at net/core/skbuff.c:214! Call Trace: skb_push (net/core/skbuff.c:2648) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82) gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920) udp_queue_rcv_one_skb (net/ipv4/udp.c:2388) ... Kernel panic - not syncing: Fatal exception in interrupt
How to fix
- Linux Linux9033fe49926f0e7421fefee922dc086417e905cf, b3c733eaae7f362601c28ac1533d47a961cd3e1c, 4fc7923871d176ce0e5fecf4a9b7bb915af790ed, 961e9b1e33445f8e42859ecc020c9f60d8b69a8b, cf45d748e437b8dd2dd987f27ee79c8c86f95c88, cd170f051dba9ac146fabcd1b91726487c0cb9fa or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 ≤ v < 9033fe49926f0e7421fefee922dc086417e905cf, 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 ≤ v < b3c733eaae7f362601c28ac1533d47a961cd3e1c, 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 ≤ v < 4fc7923871d176ce0e5fecf4a9b7bb915af790ed, 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 ≤ v < 961e9b1e33445f8e42859ecc020c9f60d8b69a8b, 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 ≤ v < cf45d748e437b8dd2dd987f27ee79c8c86f95c88, 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 ≤ v < cd170f051dba9ac146fabcd1b91726487c0cb9fa, 5.18 | 9033fe49926f0e7421fefee922dc086417e905cf, b3c733eaae7f362601c28ac1533d47a961cd3e1c, 4fc7923871d176ce0e5fecf4a9b7bb915af790ed, 961e9b1e33445f8e42859ecc020c9f60d8b69a8b, cf45d748e437b8dd2dd987f27ee79c8c86f95c88, cd170f051dba9ac146fabcd1b91726487c0cb9fa |
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