{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "00d066a4d4edbe559ba6c35153da71d4b2b8a383"
            },
            {
              "fixed": "9f948e9aede9678f4103457daf2bc9dd54c65a06"
            },
            {
              "fixed": "15a1c5f2ed2eeb3daad8d5766fd506aeda4710f3"
            },
            {
              "fixed": "2bffe379023512d280337c70faeb6a8cc435db5e"
            },
            {
              "fixed": "675ed582c1aa4d919dd535490de08c015005c653"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.12.0"
            },
            {
              "fixed": "6.12.101"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.42"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68296.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: gre: fix lltx regression for GRE tunnels with SEQ/CSUM\n\nBefore commit 00d066a4d4ed (\"netdev_features: convert NETIF_F_LLTX to\ndev-\u003elltx\"), NETIF_F_LLTX was set unconditionally in both\n__gre_tunnel_init() and ip6gre_tnl_init_features() alongside\nGRE_FEATURES:\n\n    dev-\u003efeatures |= GRE_FEATURES | NETIF_F_LLTX;\n\nWhen that commit converted NETIF_F_LLTX to the dev-\u003elltx flag, it\nplaced 'dev-\u003elltx = true' after the SEQ/CSUM early returns instead\nof before them. This causes GRE/GRETAP/ip6gre tunnels with SEQ or\nCSUM+encap to lose lockless TX, reintroducing _xmit_lock acquisition\naround their ndo_start_xmit. Since GRE xmit re-enters the stack via\nip_tunnel_xmit(), holding _xmit_lock risks ABBA deadlock with the\nunderlay device.\n\n  CPU0                        CPU1\n  ----                        ----\n  lock(\u0026qdisc_xmit_lock_key#6);\n                              lock(\u0026qdisc_xmit_lock_key#3);\n                              lock(\u0026qdisc_xmit_lock_key#6);\n  lock(\u0026qdisc_xmit_lock_key#3);\n\nFix by moving dev-\u003elltx = true before the early returns in both\nfunctions, restoring the original unconditional behavior.",
  "id": "CVE-2026-68296",
  "modified": "2026-08-12T03:51:42.562050283Z",
  "published": "2026-08-10T12:02:29.464Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/15a1c5f2ed2eeb3daad8d5766fd506aeda4710f3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2bffe379023512d280337c70faeb6a8cc435db5e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/675ed582c1aa4d919dd535490de08c015005c653"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f948e9aede9678f4103457daf2bc9dd54c65a06"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68296.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68296"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "net: gre: fix lltx regression for GRE tunnels with SEQ/CSUM"
}