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tomcat9 — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2020-13943

If an HTTP/2 client connecting to Apache Tomcat 10.0.0-M1 to 10.0.0-M7, 9.0.0.M1 to 9.0.37 or 8.5.0 to 8.5.57 exceeded the agreed maximum number of concurrent streams for a connection (in violation of the HTTP/2 protocol), it was possible that a subsequent request made on that connection could contain HTTP headers - including HTTP/2 pseudo headers - from a previous request rather than the intended headers. This could lead to users seeing responses for unexpected resources.

Products
tomcat9
Affected versions
Not specified
Fixed versions
9.0.38-1
CVEs
CVE-2020-13943
Confirmed fixed CVEs
Not specified
Updated in this feed
28 Oct 2026, 11:08 UTC · Revision 1

Source evidence

DEBIAN-CVE-2020-13943

core-osv · Original source

Published 12 Oct 2020, 14:15 UTC

If an HTTP/2 client connecting to Apache Tomcat 10.0.0-M1 to 10.0.0-M7, 9.0.0.M1 to 9.0.37 or 8.5.0 to 8.5.57 exceeded the agreed maximum number of concurrent streams for a connection (in violation of the HTTP/2 protocol), it was possible that a subsequent request made on that connection could contain HTTP headers - including HTTP/2 pseudo headers - from a previous request rather than the intended headers. This could lead to users seeing responses for unexpected resources.

osv:DEBIAN-CVE-2020-13943

tomcat9

Fixed versions: 9.0.38-1

tomcat9

Fixed versions: 9.0.38-1

tomcat9

Fixed versions: 9.0.38-1

Complete source record
{
  "id": "d4c8cb21807a9bf2473cf37a1f0ada060f02a281ab9c92e5fc89bbfba6276da3",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2020-13943",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2020-13943",
    "summary": "If an HTTP/2 client connecting to Apache Tomcat 10.0.0-M1 to 10.0.0-M7, 9.0.0.M1 to 9.0.37 or 8.5.0 to 8.5.57 exceeded the agreed maximum number of concurrent streams for a connection (in violation of the HTTP/2 protocol), it was possible that a subsequent request made on that connection could contain HTTP headers - including HTTP/2 pseudo headers - from a previous request rather than the intended headers. This could lead to users seeing responses for unexpected resources.",
    "evidence": "osv:DEBIAN-CVE-2020-13943",
    "products": [
      {
        "name": {
          "value": "tomcat9",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "9.0.38-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "tomcat9",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "9.0.38-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "tomcat9",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "9.0.38-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2020-13943",
      "aliases": [
        "DEBIAN-CVE-2020-13943"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9.0.38-1"
                }
              ]
            }
          ],
          "package": {
            "name": "tomcat9",
            "purl": "pkg:deb/debian/tomcat9?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-13943.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9.0.38-1"
                }
              ]
            }
          ],
          "package": {
            "name": "tomcat9",
            "purl": "pkg:deb/debian/tomcat9?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-13943.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9.0.38-1"
                }
              ]
            }
          ],
          "package": {
            "name": "tomcat9",
            "purl": "pkg:deb/debian/tomcat9?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-13943.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-09T09:47:35.063619308Z",
      "provider": "osv",
      "upstream": [
        "CVE-2020-13943"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2020-13943"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2020-13943",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 111686,
  "published_at": "2020-10-12T14:15:12.183+00:00"
}