CVE-2025-53506
HIGH7.5EPSS 1.2%Apache Tomcat: DoS via excessive h2 streams at connection start
Published: 7/10/2025Modified: 4/28/2026
Description
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. This 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. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other EOL versions may also be affected. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.
Affected packages (6)
- Bitnami/tomcatfrom 0, < 9.0.107, >= 10.0.0, < 10.1.43, >= 11.0.0, < 11.0.9
- Debian/tomcat10from 0, < 10.1.52-1~deb12u1
- Debian/tomcat11from 0, < 11.0.15-1~deb13u1
- Debian/tomcat9from 0, < 9.0.107-0+deb11u1
- Maven/org.apache.tomcat.embed:tomcat-embed-core>= 8.5.0, <= 8.5.100
- Maven/org.apache.tomcat:tomcat-coyote>= 11.0.0-M1, < 11.0.9
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (9)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2025-53506
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2025-53506
- PATCHhttps://github.com/apache/tomcat
- WEBhttps://github.com/apache/tomcat/commit/2aa6261276ebe50b99276953591e3a2be7898bdb
- WEBhttps://github.com/apache/tomcat/commit/434772930f362145516dd60681134e7f0cf8115b
- WEBhttps://github.com/apache/tomcat/commit/be8f330f83ceddaf3baeed57522e571572b6b99b
- WEBhttps://lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0
- WEBhttps://lists.debian.org/debian-lts-announce/2025/07/msg00009.html
- WEBhttp://www.openwall.com/lists/oss-security/2025/07/10/13