{"id":"CVE-2025-53506","aliases":["BIT-tomcat-2025-53506","GHSA-25xr-qj8w-c4vf"],"url":"https://o3.security/vulnerability/CVE-2025-53506","summary":"Apache Tomcat: DoS via excessive h2 streams at connection start","details":"Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial settings frame that reduces the maximum permitted concurrent streams.\n\nThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.8, from 10.1.0-M1 through 10.1.42, from 9.0.0.M1 through 9.0.106.\nThe following versions were EOL at the time the CVE was created but are \nknown to be affected: 8.5.0 through 8.5.100. Other EOL versions may also be affected.\n\n\nUsers are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.","published":"2025-07-10T19:14:23.249Z","modified":"2026-08-12T03:51:38.951048406Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.01991,"percentile":0.79114,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":"11.0.9"},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":"10.1.43"},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":"9.0.107"},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat-coyote","fixedVersion":null},{"ecosystem":"Maven","name":"org.apache.tomcat.embed:tomcat-embed-core","fixedVersion":null},{"ecosystem":"Maven","name":"org.apache.tomcat.embed:tomcat-embed-core","fixedVersion":"9.0.107"},{"ecosystem":"Maven","name":"org.apache.tomcat.embed:tomcat-embed-core","fixedVersion":"10.1.43"},{"ecosystem":"Maven","name":"org.apache.tomcat.embed:tomcat-embed-core","fixedVersion":"11.0.9"}],"fix":{"url":"https://github.com/apache/tomcat/commit/2aa6261276ebe50b99276953591e3a2be7898bdb","label":"apache/tomcat@2aa6261"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2025/07/10/13"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/07/msg00009.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/53xxx/CVE-2025-53506.json"},{"type":"ADVISORY","url":"https://lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-53506"},{"type":"WEB","url":"https://github.com/apache/tomcat/commit/2aa6261276ebe50b99276953591e3a2be7898bdb"},{"type":"WEB","url":"https://github.com/apache/tomcat/commit/434772930f362145516dd60681134e7f0cf8115b"},{"type":"WEB","url":"https://github.com/apache/tomcat/commit/be8f330f83ceddaf3baeed57522e571572b6b99b"},{"type":"PACKAGE","url":"https://github.com/apache/tomcat"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:38.951048406Z"}}