ubuntu-cve-2021-30639
Vulnerability from osv_ubuntu
Published
2021-07-12 15:15
Modified
2025-07-14 04:36
Summary
Details

A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests. This meant that once a non-blocking I/O error occurred, all future requests handled by that request object would fail. Users were able to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability. This issue affects Apache Tomcat 10.0.3 to 10.0.4; 9.0.44; 8.5.64.

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": {},
      "package": {
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        "name": "tomcat6",
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      },
      "ranges": [
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            }
          ],
          "type": "ECOSYSTEM"
        }
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        "6.0.39-1",
        "6.0.39-1ubuntu0.1",
        "6.0.39-1ubuntu0.1+esm1",
        "6.0.39-1ubuntu0.1+esm2"
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "tomcat7",
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      },
      "ranges": [
        {
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          ],
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        "7.0.47-1",
        "7.0.50-1",
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        "7.0.52-1ubuntu0.1",
        "7.0.52-1ubuntu0.3",
        "7.0.52-1ubuntu0.6",
        "7.0.52-1ubuntu0.7",
        "7.0.52-1ubuntu0.8",
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        "7.0.52-1ubuntu0.14",
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      "ecosystem_specific": {},
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      "ecosystem_specific": {},
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    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "tomcat7",
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      },
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        "7.0.68-1ubuntu0.4",
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        "7.0.68-1ubuntu0.4+esm2",
        "7.0.68-1ubuntu0.4+esm3"
      ]
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    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "tomcat7",
        "purl": "pkg:deb/ubuntu/tomcat7@7.0.78-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
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          "events": [
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      "versions": [
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        "7.0.78-1ubuntu0.1~esm1"
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    },
    {
      "ecosystem_specific": {},
      "package": {
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        "name": "tomcat8",
        "purl": "pkg:deb/ubuntu/tomcat8@8.5.39-1ubuntu1~18.04.3+esm5?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
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            }
          ],
          "type": "ECOSYSTEM"
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      ],
      "versions": [
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        "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"
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    },
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      "ecosystem_specific": {},
      "package": {
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        "purl": "pkg:deb/ubuntu/tomcat9@9.0.16-3ubuntu0.18.04.2+esm7?arch=source\u0026distro=esm-apps/bionic"
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        "9.0.16-3ubuntu0.18.04.2+esm6",
        "9.0.16-3ubuntu0.18.04.2+esm7"
      ]
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      "ecosystem_specific": {},
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        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "tomcat9",
        "purl": "pkg:deb/ubuntu/tomcat9@9.0.31-1ubuntu0.9+esm2?arch=source\u0026distro=esm-apps/focal"
      },
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        "9.0.31-1ubuntu0.3",
        "9.0.31-1ubuntu0.4",
        "9.0.31-1ubuntu0.5",
        "9.0.31-1ubuntu0.6",
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        "9.0.31-1ubuntu0.8",
        "9.0.31-1ubuntu0.9",
        "9.0.31-1ubuntu0.9+esm1",
        "9.0.31-1ubuntu0.9+esm2"
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    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "tomcat9",
        "purl": "pkg:deb/ubuntu/tomcat9@9.0.58-1ubuntu0.2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
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      "ecosystem_specific": {},
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        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "tomcat9",
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      "ranges": [
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        "9.0.70-2",
        "9.0.70-2ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:25.04",
        "name": "tomcat9",
        "purl": "pkg:deb/ubuntu/tomcat9@9.0.70-2ubuntu1.25.04.2?arch=source\u0026distro=plucky"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
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      ],
      "versions": [
        "9.0.70-2ubuntu1.1",
        "9.0.70-2ubuntu1.25.04.1",
        "9.0.70-2ubuntu1.25.04.2"
      ]
    }
  ],
  "aliases": [],
  "details": "A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests. This meant that once a non-blocking I/O error occurred, all future requests handled by that request object would fail. Users were able to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability. This issue affects Apache Tomcat 10.0.3 to 10.0.4; 9.0.44; 8.5.64.",
  "id": "UBUNTU-CVE-2021-30639",
  "modified": "2025-07-14T04:36:57Z",
  "published": "2021-07-12T15:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-30639"
    },
    {
      "type": "REPORT",
      "url": "https://bz.apache.org/bugzilla/show_bug.cgi?id=65203"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/apache/tomcat/commit/8ece47c4a9fb9349e8862c84358a4dd23c643a24"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/apache/tomcat/commit/411caf29ac1c16e6ac291b6e5543b2371dbd25e2"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/rd84fae1f474597bdf358f5bdc0a5c453c507bd527b83e8be6b5ea3f4%40%3Cannounce.tomcat.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf@%3Cusers.tomcat.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf@%3Cdev.tomcat.apache.org%3E"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-30639"
    }
  ],
  "related": [],
  "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-2021-30639"
  ],
  "withdrawn": "2025-08-21T16:42:12Z"
}



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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.