{"id":"CVE-2026-23277","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit\n\nteql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit\nthrough slave devi…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit\n\nteql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit\nthrough slave devi…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-476"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.5, < 5.10.253","linux_kernel >= 5.11, < 5.15.203","linux_kernel >= 5.16, < 6.1.167","linux_kernel >= 6.2, < 6.6.130","linux_kernel >= 6.7, < 6.12.78","linux_kernel >= 6.13, < 6.18.19","linux_kernel >= 6.19, < 6.19.9","linux_kernel = 7.0"],"patched":["linux_kernel 6.19.9"],"published":"2026-03-20","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:46.220","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-23277","references":[{"url":"https://git.kernel.org/stable/c/0bad9c86edd22dec4df83c2b29872d66fd8a2ff4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0cc0c2e661af418bbf7074179ea5cfffc0a5c466","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/21ea283c2750c8307aa35ee832b0951cc993c27d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/383493b9940e3d1b5517424081b3e072e20ec43c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/57c153249143333bbf4ecf927bdf8aa2696ee397","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/59b06d8b9bdb6b64b3c534c18da68bce5ccd31be","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6b1f563d670162e188a0f2aec39c24b67b106e17","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/81a43e8005366f16e629d8c95dfe05beaa8d36a7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00125,"epssPercentile":0.02159,"ingestedAt":"2026-09-08T15:33:26.993Z","slug":"CVE-2026-23277","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit\n\nteql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit\nthrough slave devices, but does not update skb->dev to the slave device\nbeforehand.\n\nWhen a gretap tunnel is a TEQL slave, the transmit path reaches\niptunnel_xmit() which saves dev = skb->dev (still pointing to teql0\nmaster) and later calls iptunnel_xmit_stats(dev, pkt_len). This\nfunction does:\n\n    get_cpu_ptr(dev->tstats)\n\nSince teql_master_setup() does not set dev->pcpu_stat_type to\nNETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats\nfor teql0, so dev->tstats is NULL. get_cpu_ptr(NULL) computes\nNULL + __per_cpu_offset[cpu], resulting in a page fault.\n\n BUG: unable to handle page fault for address: ffff8880e6659018\n #PF: supervisor write access in kernel mode\n #PF: error_code(0x0002) - not-present page\n PGD 68bc067 P4D 68bc067 PUD 0\n Oops: Oops: 0002 [#1] SMP KASAN PTI\n RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89)\n Call Trace:\n  <TASK>\n  ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)\n  __gre_xmit (net/ipv4/ip_gre.c:478)\n  gre_tap_xmit (net/ipv4/ip_gre.c:779)\n  teql_master_xmit (net/sched/sch_teql.c:319)\n  dev_hard_start_xmit (net/core/dev.c:3887)\n  sch_direct_xmit (net/sched/sch_generic.c:347)\n  __dev_queue_xmit (net/core/dev.c:4802)\n  neigh_direct_output (net/core/neighbour.c:1660)\n  ip_finish_output2 (net/ipv4/ip_output.c:237)\n  __ip_finish_output.part.0 (net/ipv4/ip_output.c:315)\n  ip_mc_output (net/ipv4/ip_output.c:369)\n  ip_send_skb (net/ipv4/ip_output.c:1508)\n  udp_send_skb (net/ipv4/udp.c:1195)\n  udp_sendmsg (net/ipv4/udp.c:1485)\n  inet_sendmsg (net/ipv4/af_inet.c:859)\n  __sys_sendto (net/socket.c:2206)\n\nFix this by setting skb->dev = slave before calling\nnetdev_start_xmit(), so that tunnel xmit functions see the correct\nslave device with properly allocated tstats.\n\n## Affected\n\n- `linux_kernel >= 4.5, < 5.10.253`\n- `linux_kernel >= 5.11, < 5.15.203`\n- `linux_kernel >= 5.16, < 6.1.167`\n- `linux_kernel >= 6.2, < 6.6.130`\n- `linux_kernel >= 6.7, < 6.12.78`\n- `linux_kernel >= 6.13, < 6.18.19`\n- `linux_kernel >= 6.19, < 6.19.9`\n- `linux_kernel = 7.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.19.9`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221643,"id":"CVE-2026-23277","ts":1792035301722,"field":"cvss","old":null,"new":"5.5"},{"seq":221642,"id":"CVE-2026-23277","ts":1792035301722,"field":"severity","old":"none","new":"medium"}]}