{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "046c052b475e7119b6a30e3483e2888fc606a2f8"
            },
            {
              "fixed": "be3bfcb34bda04f6a350710db471d4133f950f2c"
            },
            {
              "fixed": "0de7db2eb27e82b983157016fa604b1ba664ae5f"
            },
            {
              "fixed": "790093245e35040c2adb15f48970020425aa3f47"
            },
            {
              "fixed": "2cd7e6971fc2787408ceef17906ea152791448cf"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "6.12.95"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.37"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53070.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: disable BH before calling udp_tunnel_xmit_skb()\n\nudp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with\nBH disabled.  After commit 6f1a9140ecda (\"add xmit recursion limit to\ntunnel xmit functions\"), on the path:\n\n  udp(6)_tunnel_xmit_skb() -\u003e ip(6)tunnel_xmit()\n\ndev_xmit_recursion_inc()/dec() must stay balanced on the same CPU.\n\nWithout local_bh_disable(), the context may move between CPUs, which can\nbreak the inc/dec pairing. This may lead to incorrect recursion level\ndetection and cause packets to be dropped in ip(6)_tunnel_xmit() or\n__dev_queue_xmit().\n\nFix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths.\n\nIn my testing, after enabling the SCTP over UDP:\n\n  # ip net exec ha sysctl -w net.sctp.udp_port=9899\n  # ip net exec ha sysctl -w net.sctp.encap_port=9899\n  # ip net exec hb sysctl -w net.sctp.udp_port=9899\n  # ip net exec hb sysctl -w net.sctp.encap_port=9899\n\n  # ip net exec ha iperf3 -s\n\n- without this patch:\n\n  # ip net exec hb iperf3 -c 192.168.0.1 --sctp\n  [  5]   0.00-10.00  sec  37.2 MBytes  31.2 Mbits/sec  sender\n  [  5]   0.00-10.00  sec  37.1 MBytes  31.1 Mbits/sec  receiver\n\n- with this patch:\n\n  # ip net exec hb iperf3 -c 192.168.0.1 --sctp\n  [  5]   0.00-10.00  sec  3.14 GBytes  2.69 Gbits/sec  sender\n  [  5]   0.00-10.00  sec  3.14 GBytes  2.69 Gbits/sec  receiver",
  "id": "CVE-2026-53070",
  "modified": "2026-07-16T03:31:05.311937745Z",
  "published": "2026-06-24T16:30:11.816Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0de7db2eb27e82b983157016fa604b1ba664ae5f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2cd7e6971fc2787408ceef17906ea152791448cf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/790093245e35040c2adb15f48970020425aa3f47"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be3bfcb34bda04f6a350710db471d4133f950f2c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53070.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53070"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "sctp: disable BH before calling udp_tunnel_xmit_skb()"
}