5.5

CVE-2026-23277: linux NULL Pointer Dereference

CVSS: 5.5v3.1MediumModified
AliasesUBUNTU-CVE-2026-23277DEBIAN-CVE-2026-23277
Published 20-03-2026Last modified 15-10-2026
Open JSON

Vulnerability summary

CVE-2026-23277 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 1.9% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.13%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 34 · Related 34
OPENSUSE-SU-2026:20572-1SUSE-SU-2026:1573-1SUSE-SU-2026:21114-1SUSE-SU-2026:21123-1SUSE-SU-2026:21230-1SUSE-SU-2026:21237-1

Timeline

  1. 20-03-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.13%

Chance of exploitation in the next 30 days

Percentile

2%

Versus all other CVEs

30-day change

0.00 pp

From 0.12% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.13%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu156 products
  • linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-136.136
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1061.64
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 383493b9940e3d1b5517424081b3e072e20ec43c | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 6b1f563d670162e188a0f2aec39c24b67b106e17 | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 57c153249143333bbf4ecf927bdf8aa2696ee397 | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 59b06d8b9bdb6b64b3c534c18da68bce5ccd31be | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 81a43e8005366f16e629d8c95dfe05beaa8d36a7 | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 0bad9c86edd22dec4df83c2b29872d66fd8a2ff4 | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 21ea283c2750c8307aa35ee832b0951cc993c27d | ≥ 039f50629b7f860f36644ed1f34b27da9aa62f43, < 0cc0c2e661af418bbf7074179ea5cfffc0a5c466 | 4.5
  • linux_kernel≥ 4.5, < 5.10.253 | ≥ 5.11, < 5.15.203 | ≥ 5.16, < 6.1.167 | ≥ 6.2, < 6.6.130 | ≥ 6.7, < 6.12.78 | ≥ 6.13, < 6.18.19 | ≥ 6.19, < 6.19.9 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3
Debian1 product
  • linux< 6.1.170-1 | < 6.12.85-1 | < 6.19.10-1

3 vendors · 159 products

References

43 links
Show all 43 references