CVE-2026-53070 (GCVE-0-2026-53070)

Vulnerability from cvelistv5 – Published: 2026-06-24 16:30 – Updated: 2026-06-28 06:38
VLAI
Title
sctp: disable BH before calling udp_tunnel_xmit_skb()
Summary
In the Linux kernel, the following vulnerability has been resolved: sctp: disable BH before calling udp_tunnel_xmit_skb() udp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with BH disabled. After commit 6f1a9140ecda ("add xmit recursion limit to tunnel xmit functions"), on the path: udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit() dev_xmit_recursion_inc()/dec() must stay balanced on the same CPU. Without local_bh_disable(), the context may move between CPUs, which can break the inc/dec pairing. This may lead to incorrect recursion level detection and cause packets to be dropped in ip(6)_tunnel_xmit() or __dev_queue_xmit(). Fix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths. In my testing, after enabling the SCTP over UDP: # ip net exec ha sysctl -w net.sctp.udp_port=9899 # ip net exec ha sysctl -w net.sctp.encap_port=9899 # ip net exec hb sysctl -w net.sctp.udp_port=9899 # ip net exec hb sysctl -w net.sctp.encap_port=9899 # ip net exec ha iperf3 -s - without this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 37.2 MBytes 31.2 Mbits/sec sender [ 5] 0.00-10.00 sec 37.1 MBytes 31.1 Mbits/sec receiver - with this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec sender [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec receiver
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 046c052b475e7119b6a30e3483e2888fc606a2f8 , < 0de7db2eb27e82b983157016fa604b1ba664ae5f (git)
Affected: 046c052b475e7119b6a30e3483e2888fc606a2f8 , < 790093245e35040c2adb15f48970020425aa3f47 (git)
Affected: 046c052b475e7119b6a30e3483e2888fc606a2f8 , < 2cd7e6971fc2787408ceef17906ea152791448cf (git)
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Linux Linux Affected: 5.11
Unaffected: 0 , < 5.11 (semver)
Unaffected: 6.18.37 , ≤ 6.18.* (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sctp/ipv6.c",
            "net/sctp/protocol.c"
          ],
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          ],
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "5.11"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "version": "6.18.37",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
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      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.37",
                  "versionStartIncluding": "5.11",
                  "vulnerable": true
                },
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                  "versionEndExcluding": "7.0.10",
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                  "versionStartIncluding": "5.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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"
        }
      ],
      "metrics": [
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          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-28T06:38:54.908Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0de7db2eb27e82b983157016fa604b1ba664ae5f"
        },
        {
          "url": "https://git.kernel.org/stable/c/790093245e35040c2adb15f48970020425aa3f47"
        },
        {
          "url": "https://git.kernel.org/stable/c/2cd7e6971fc2787408ceef17906ea152791448cf"
        }
      ],
      "title": "sctp: disable BH before calling udp_tunnel_xmit_skb()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53070",
    "datePublished": "2026-06-24T16:30:11.816Z",
    "dateReserved": "2026-06-09T07:44:35.382Z",
    "dateUpdated": "2026-06-28T06:38:54.908Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-53070",
      "date": "2026-07-02",
      "epss": "0.00339",
      "percentile": "0.25836"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-53070\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-06-24T17:17:20.513\",\"lastModified\":\"2026-06-28T08:16:32.403\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/sctp/ipv6.c\",\"net/sctp/protocol.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"046c052b475e7119b6a30e3483e2888fc606a2f8\",\"lessThan\":\"0de7db2eb27e82b983157016fa604b1ba664ae5f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"046c052b475e7119b6a30e3483e2888fc606a2f8\",\"lessThan\":\"790093245e35040c2adb15f48970020425aa3f47\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"046c052b475e7119b6a30e3483e2888fc606a2f8\",\"lessThan\":\"2cd7e6971fc2787408ceef17906ea152791448cf\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/sctp/ipv6.c\",\"net/sctp/protocol.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.11\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.11\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.37\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.10\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0de7db2eb27e82b983157016fa604b1ba664ae5f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2cd7e6971fc2787408ceef17906ea152791448cf\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/790093245e35040c2adb15f48970020425aa3f47\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.