VulnerabilityPublished 20 Mar 2026Updated 5 Nov 2026

CVE-2026-23277: Linux kernel · net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit

Affects Linux kernelSource CVE Database V5

Compare

Not known to be exploited · fixed in 383493b9940e3d1b5517424081b3e072e20ec43c : update Linux kernel when convenient.

Data as of 5 Nov 2026, 23:24 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

EPSS

0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in 383493b9940e3d1b5517424081b3e072e20ec43c, 81a43e8005366f16e629d8c95dfe05beaa8d36a7, 59b06d8b9bdb6b64b3c534c18da68bce5ccd31be +5

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 383493b9940e3d1b5517424081b3e072e20ec43c	Fixed in 383493b9940e3d1b5517424081b3e072e20ec43c
LinuxLinux	Affected ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 81a43e8005366f16e629d8c95dfe05beaa8d36a7	Fixed in 81a43e8005366f16e629d8c95dfe05beaa8d36a7
LinuxLinux	Affected ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 59b06d8b9bdb6b64b3c534c18da68bce5ccd31be	Fixed in 59b06d8b9bdb6b64b3c534c18da68bce5ccd31be
LinuxLinux	Affected ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 57c153249143333bbf4ecf927bdf8aa2696ee397	Fixed in 57c153249143333bbf4ecf927bdf8aa2696ee397
LinuxLinux	Affected ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 21ea283c2750c8307aa35ee832b0951cc993c27d	Fixed in 21ea283c2750c8307aa35ee832b0951cc993c27d
LinuxLinux	Affected ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 6b1f563d670162e188a0f2aec39c24b67b106e17	Fixed in 6b1f563d670162e188a0f2aec39c24b67b106e17

Description

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.

References

Community reviews

Loading reviews…