{"cve":"CVE-2020-13943","nvd":{"published":"2020-10-12T14:15:12.183","modified":"2026-10-08T22:16:56.900","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","score":4.3},"cwes":[],"references":["http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00002.html","http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00021.html","https://lists.apache.org/thread.html/r4a390027eb27e4550142fac6c8317cc684b157ae314d31514747f307%40%3Cannounce.tomcat.apache.org%3E","https://lists.debian.org/debian-lts-announce/2020/10/msg00019.html","https://security.netapp.com/advisory/ntap-20201016-0007/"],"products":["apache:tomcat","debian:debian_linux","oracle:instantis_enterprisetrack","oracle:sd-wan_edge"],"source":"nvd","synced_at":"2026-10-19T21:09:53.489947993+00:00"},"epss":{"cve":"CVE-2020-13943","score":0.54966,"percentile":0.99019,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-f268-65qc-98vg","url":"https://osv.dev/vulnerability/GHSA-f268-65qc-98vg","summary":"Exposure of Sensitive Information to an Unauthorized Actor in Apache Tomcat","modified":"2024-02-16T08:04:48.542136Z","packages":[{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","purl":"pkg:maven/org.apache.tomcat/tomcat-coyote","ranges":[">=10.0.0-M1 <10.0.0-M8"],"fixed":["10.0.0-M8"]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","purl":"pkg:maven/org.apache.tomcat/tomcat-coyote","ranges":[">=9.0.0-M1 <9.0.38"],"fixed":["9.0.38"]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","purl":"pkg:maven/org.apache.tomcat/tomcat-coyote","ranges":[">=8.5.0 <8.5.58"],"fixed":["8.5.58"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}