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

{
  "id": "35d53dfd0574a373312baeebf53fc2b33dde5adcdedcbe4b1083f0fe502b70e6",
  "url": "https://osv.dev/vulnerability/CVE-2026-23277",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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 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: 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.",
    "evidence": "osv:CVE-2026-23277",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.253",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.203",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.167",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.130",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.78",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.19",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-23277",
      "aliases": [
        "CVE-2026-23277"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "039f50629b7f860f36644ed1f34b27da9aa62f43"
                },
                {
                  "fixed": "383493b9940e3d1b5517424081b3e072e20ec43c"
                },
                {
                  "fixed": "6b1f563d670162e188a0f2aec39c24b67b106e17"
                },
                {
                  "fixed": "57c153249143333bbf4ecf927bdf8aa2696ee397"
                },
                {
                  "fixed": "59b06d8b9bdb6b64b3c534c18da68bce5ccd31be"
                },
                {
                  "fixed": "81a43e8005366f16e629d8c95dfe05beaa8d36a7"
                },
                {
                  "fixed": "0bad9c86edd22dec4df83c2b29872d66fd8a2ff4"
                },
                {
                  "fixed": "21ea283c2750c8307aa35ee832b0951cc993c27d"
                },
                {
                  "fixed": "0cc0c2e661af418bbf7074179ea5cfffc0a5c466"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23277.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.5.0"
                },
                {
                  "fixed": "5.10.253"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.203"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.167"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.130"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.78"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.19"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "6.19.9"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23277.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.929596972Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-082556.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-784472.html",
        "https://git.kernel.org/stable/c/0bad9c86edd22dec4df83c2b29872d66fd8a2ff4",
        "https://git.kernel.org/stable/c/0cc0c2e661af418bbf7074179ea5cfffc0a5c466",
        "https://git.kernel.org/stable/c/21ea283c2750c8307aa35ee832b0951cc993c27d",
        "https://git.kernel.org/stable/c/383493b9940e3d1b5517424081b3e072e20ec43c",
        "https://git.kernel.org/stable/c/57c153249143333bbf4ecf927bdf8aa2696ee397",
        "https://git.kernel.org/stable/c/59b06d8b9bdb6b64b3c534c18da68bce5ccd31be",
        "https://git.kernel.org/stable/c/6b1f563d670162e188a0f2aec39c24b67b106e17",
        "https://git.kernel.org/stable/c/81a43e8005366f16e629d8c95dfe05beaa8d36a7",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23277.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-23277",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23277.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-23277",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 502197,
  "published_at": "2026-03-20T08:08:57.394+00:00"
}