---
id: CVE-2026-23277
title: >-
  net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave
  xmit
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave
  xmit


  teql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit

  through slave devi…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    383493b9940e3d1b5517424081b3e072e20ec43c
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    6b1f563d670162e188a0f2aec39c24b67b106e17
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    57c153249143333bbf4ecf927bdf8aa2696ee397
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    59b06d8b9bdb6b64b3c534c18da68bce5ccd31be
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    81a43e8005366f16e629d8c95dfe05beaa8d36a7
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    0bad9c86edd22dec4df83c2b29872d66fd8a2ff4
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    21ea283c2750c8307aa35ee832b0951cc993c27d
  - >-
    Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 <
    0cc0c2e661af418bbf7074179ea5cfffc0a5c466
  - Linux 4.5
published: '2026-03-20'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:45:19.497Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23277'
references:
  - url: 'https://git.kernel.org/stable/c/383493b9940e3d1b5517424081b3e072e20ec43c'
  - url: 'https://git.kernel.org/stable/c/6b1f563d670162e188a0f2aec39c24b67b106e17'
  - url: 'https://git.kernel.org/stable/c/57c153249143333bbf4ecf927bdf8aa2696ee397'
  - url: 'https://git.kernel.org/stable/c/59b06d8b9bdb6b64b3c534c18da68bce5ccd31be'
  - url: 'https://git.kernel.org/stable/c/81a43e8005366f16e629d8c95dfe05beaa8d36a7'
  - url: 'https://git.kernel.org/stable/c/0bad9c86edd22dec4df83c2b29872d66fd8a2ff4'
  - url: 'https://git.kernel.org/stable/c/21ea283c2750c8307aa35ee832b0951cc993c27d'
  - url: 'https://git.kernel.org/stable/c/0cc0c2e661af418bbf7074179ea5cfffc0a5c466'
tags:
  - cve.org
epss: 0.00122
epssPercentile: 0.01738
ingestedAt: '2026-09-08T15:33:26.993Z'
---

## Overview

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

net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit

teql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit
through slave devices, but does not update skb->dev to the slave device
beforehand.

When a gretap tunnel is a TEQL slave, the transmit path reaches
iptunnel_xmit() which saves dev = skb->dev (still pointing to teql0
master) and later calls iptunnel_xmit_stats(dev, pkt_len). This
function does:

    get_cpu_ptr(dev->tstats)

Since teql_master_setup() does not set dev->pcpu_stat_type to
NETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats
for teql0, so dev->tstats is NULL. get_cpu_ptr(NULL) computes
NULL + __per_cpu_offset[cpu], resulting in a page fault.

 BUG: unable to handle page fault for address: ffff8880e6659018
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 PGD 68bc067 P4D 68bc067 PUD 0
 Oops: Oops: 0002 [#1] SMP KASAN PTI
 RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89)
 Call Trace:
  <TASK>
  ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)
  __gre_xmit (net/ipv4/ip_gre.c:478)
  gre_tap_xmit (net/ipv4/ip_gre.c:779)
  teql_master_xmit (net/sched/sch_teql.c:319)
  dev_hard_start_xmit (net/core/dev.c:3887)
  sch_direct_xmit (net/sched/sch_generic.c:347)
  __dev_queue_xmit (net/core/dev.c:4802)
  neigh_direct_output (net/core/neighbour.c:1660)
  ip_finish_output2 (net/ipv4/ip_output.c:237)
  __ip_finish_output.part.0 (net/ipv4/ip_output.c:315)
  ip_mc_output (net/ipv4/ip_output.c:369)
  ip_send_skb (net/ipv4/ip_output.c:1508)
  udp_send_skb (net/ipv4/udp.c:1195)
  udp_sendmsg (net/ipv4/udp.c:1485)
  inet_sendmsg (net/ipv4/af_inet.c:859)
  __sys_sendto (net/socket.c:2206)

Fix this by setting skb->dev = slave before calling
netdev_start_xmit(), so that tunnel xmit functions see the correct
slave device with properly allocated tstats.

## Affected

- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 383493b9940e3d1b5517424081b3e072e20ec43c`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 6b1f563d670162e188a0f2aec39c24b67b106e17`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 57c153249143333bbf4ecf927bdf8aa2696ee397`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 59b06d8b9bdb6b64b3c534c18da68bce5ccd31be`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 81a43e8005366f16e629d8c95dfe05beaa8d36a7`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 0bad9c86edd22dec4df83c2b29872d66fd8a2ff4`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 21ea283c2750c8307aa35ee832b0951cc993c27d`
- `Linux >= 039f50629b7f860f36644ed1f34b27da9aa62f43 < 0cc0c2e661af418bbf7074179ea5cfffc0a5c466`
- `Linux 4.5`

## Remediation

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