---
id: CVE-2026-64577
title: |-
  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
summary: |-
  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 guara…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
published: '2026-08-05'
updated: '2026-08-08'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64577'
references:
  - url: 'https://git.kernel.org/stable/c/4fc7923871d176ce0e5fecf4a9b7bb915af790ed'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/961e9b1e33445f8e42859ecc020c9f60d8b69a8b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b3c733eaae7f362601c28ac1533d47a961cd3e1c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cd170f051dba9ac146fabcd1b91726487c0cb9fa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cf45d748e437b8dd2dd987f27ee79c8c86f95c88'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00576
epssPercentile: 0.46233
ingestedAt: '2026-08-08T20:29:49.387Z'
---

## Overview

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

## Remediation

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