{"id":"CVE-2020-13943","aliases":["BIT-tomcat-2020-13943","GHSA-f268-65qc-98vg"],"url":"https://o3.security/vulnerability/CVE-2020-13943","summary":"Exposure of Sensitive Information to an Unauthorized Actor in Apache Tomcat","details":"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.","published":"2020-10-12T14:15:12.183Z","modified":"2026-07-08T05:53:36.707116318Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"},"epss":{"score":0.57286,"percentile":0.99028,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":"10.0.0-M8"},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":"9.0.38"},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":"8.5.58"}],"fix":null,"references":[{"type":"WEB","url":"http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00021.html"},{"type":"ADVISORY","url":"http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00002.html"},{"type":"ADVISORY","url":"https://lists.apache.org/thread.html/r4a390027eb27e4550142fac6c8317cc684b157ae314d31514747f307%40%3Cannounce.tomcat.apache.org%3E"},{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2020/10/msg00019.html"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20201016-0007/"},{"type":"ADVISORY","url":"https://www.debian.org/security/2021/dsa-4835"},{"type":"FIX","url":"https://www.oracle.com/security-alerts/cpuApr2021.html"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T05:53:36.707116318Z"}}