ubuntu-cve-2020-11996
Vulnerability from osv_ubuntu
Published
2020-06-26 17:15
Modified
2026-06-10 07:24
Summary
Details

A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5.0 to 8.5.55 could trigger high CPU usage for several seconds. If a sufficient number of such requests were made on concurrent HTTP/2 connections, the server could become unresponsive.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libtomcat8-embed-java",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "libtomcat8-java",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "tomcat8",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "tomcat8-admin",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "tomcat8-common",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "tomcat8-docs",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "tomcat8-examples",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          },
          {
            "binary_name": "tomcat8-user",
            "binary_version": "8.5.39-1ubuntu1~18.04.3+esm5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "tomcat8",
        "purl": "pkg:deb/ubuntu/tomcat8@8.5.39-1ubuntu1~18.04.3+esm5?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.5.21-1ubuntu1",
        "8.5.29-1",
        "8.5.30-1",
        "8.5.30-1ubuntu1",
        "8.5.30-1ubuntu1.2",
        "8.5.30-1ubuntu1.3",
        "8.5.30-1ubuntu1.4",
        "8.5.39-1ubuntu1~18.04.1",
        "8.5.39-1ubuntu1~18.04.2",
        "8.5.39-1ubuntu1~18.04.3",
        "8.5.39-1ubuntu1~18.04.3+esm1",
        "8.5.39-1ubuntu1~18.04.3+esm2",
        "8.5.39-1ubuntu1~18.04.3+esm3",
        "8.5.39-1ubuntu1~18.04.3+esm4",
        "8.5.39-1ubuntu1~18.04.3+esm5"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libtomcat9-embed-java",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "libtomcat9-java",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "tomcat9",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "tomcat9-admin",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "tomcat9-common",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "tomcat9-docs",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "tomcat9-examples",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          },
          {
            "binary_name": "tomcat9-user",
            "binary_version": "9.0.16-3ubuntu0.18.04.2+esm8"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "tomcat9",
        "purl": "pkg:deb/ubuntu/tomcat9@9.0.16-3ubuntu0.18.04.2+esm8?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.0.16-3~18.04.1",
        "9.0.16-3ubuntu0.18.04.1",
        "9.0.16-3ubuntu0.18.04.2",
        "9.0.16-3ubuntu0.18.04.2+esm1",
        "9.0.16-3ubuntu0.18.04.2+esm2",
        "9.0.16-3ubuntu0.18.04.2+esm3",
        "9.0.16-3ubuntu0.18.04.2+esm4",
        "9.0.16-3ubuntu0.18.04.2+esm5",
        "9.0.16-3ubuntu0.18.04.2+esm6",
        "9.0.16-3ubuntu0.18.04.2+esm7",
        "9.0.16-3ubuntu0.18.04.2+esm8"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libtomcat9-embed-java",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "libtomcat9-java",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "tomcat9",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "tomcat9-admin",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "tomcat9-common",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "tomcat9-docs",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "tomcat9-examples",
            "binary_version": "9.0.31-1ubuntu0.1"
          },
          {
            "binary_name": "tomcat9-user",
            "binary_version": "9.0.31-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "tomcat9",
        "purl": "pkg:deb/ubuntu/tomcat9@9.0.31-1ubuntu0.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "9.0.31-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.0.24-1",
        "9.0.27-1",
        "9.0.31-1"
      ]
    }
  ],
  "aliases": [],
  "details": "A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5.0 to 8.5.55 could trigger high CPU usage for several seconds. If a sufficient number of such requests were made on concurrent HTTP/2 connections, the server could become unresponsive.",
  "id": "UBUNTU-CVE-2020-11996",
  "modified": "2026-06-10T07:24:15Z",
  "published": "2020-06-26T17:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2020-11996"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2020/06/25/6"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/apache/tomcat/commit/9a0231683a77e2957cea0fdee88b193b30b0c976"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/apache/tomcat/commit/c8acd2ab7371e39aeca7c306f3b5380f00afe552"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r74f5a8204efe574cbfcd95b2a16236fe95beb45c4d9fee3dc789dca9@%3Ccommits.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r8f3d416c193bc9384a8a7dd368623d441f5fcaff1057115008100561@%3Ccommits.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r8f7484589454638af527182ae55ef5b628ba00c05c5b11887c922fb1@%3Cnotifications.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r93ca628ef3a4530dfe5ac49fddc795f0920a4b2a408b57a30926a42b@%3Ccommits.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/ra7092f7492569b39b04ec0decf52628ba86c51f15efb38f5853e2760@%3Cnotifications.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/rb4ee49ecc4c59620ffd5e66e84a17e526c2c3cfa95d0cd682d90d338@%3Cnotifications.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/rb820f1a2a02bf07414be12c653c2ab5321fd87b9bf6c5e635c53ff4b@%3Cnotifications.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/rc80b96b4b96618b2b7461cb90664a428cfd6605eea9f74e51b792542@%3Cnotifications.ofbiz.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/rea65d6ef2e45dd1c45faae83922042732866c7b88fa109b76c83db52@%3Cnotifications.ofbiz.apache.org%3E"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4596-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2020-11996"
    }
  ],
  "related": [
    "USN-4596-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2020-11996"
  ]
}



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Sightings

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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.