# CVE-2019-0199: Apache Tomcat Denial of Service vulnerability > Attackers can cause thread exhaustion and denial of service in Apache Tomcat by sending excessive HTTP/2 SETTINGS frames and keeping streams open. - **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 10 Apr 2019 - **Updated:** 4 Aug 2024 - **Also known as:** DEBIAN-CVE-2019-0199, GHSA-qcxh-w3j9-58qr, SUSE-SU-2019:1825-1, UBUNTU-CVE-2019-0199, openSUSE-SU-2019:1723-1 ## What is CVE-2019-0199? CVE-2019-0199 is a high-severity denial of service vulnerability in Apache Tomcat, published on 10 Apr 2019. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description The HTTP/2 implementation in Apache Tomcat 9.0.0.M1 to 9.0.14 and 8.5.0 to 8.5.37 accepted streams with excessive numbers of SETTINGS frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS. Weakness: CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2019-0199? 8 open source packages ship an affected version, including org.apache.tomcat.embed:tomcat-embed-core and org.apache.tomcat:tomcat-coyote. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 8.0.0 | 8.5.38 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 8.0.0 | 8.5.38 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 9.0.0 | 9.0.16 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 9.0.0 | 9.0.16 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 8.0.0 | 8.5.38 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 8.0.0 | 8.5.38 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 9.0.0 | 9.0.16 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 9.0.0 | 9.0.16 | | `tomcat` | SUSE:Linux Enterprise Module for Web and Scripting 15 | All versions | 9.0.21-3.27.1 | | `tomcat` | openSUSE:Leap 15.0 | All versions | 9.0.21-lp150.2.22.1 | Products: Apache Tomcat. ## How do I fix CVE-2019-0199? Upgrade org.apache.tomcat.embed:tomcat-embed-core to a fixed version for your release line: 8.5.38 or 9.0.16. ## Is CVE-2019-0199 being exploited? There is no known exploitation of CVE-2019-0199 in the wild and no public exploit code. ## Other vulnerabilities in Apache Tomcat - [CVE-2025-24813](https://insights.sbomify.com/CVE-2025-24813/): Apache Tomcat Path Equivalence (critical 10.0, exploited in the wild) - [CVE-2016-8735](https://insights.sbomify.com/CVE-2016-8735/): Apache Tomcat Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2017-12617](https://insights.sbomify.com/CVE-2017-12617/): Apache Tomcat Remote Code Execution (high 8.1, exploited in the wild) - [CVE-2017-12615](https://insights.sbomify.com/CVE-2017-12615/): Apache Tomcat on Windows Remote Code Execution (high 8.1, exploited in the wild) - [CVE-2026-34486](https://insights.sbomify.com/CVE-2026-34486/): Apache Tomcat Missing Encryption of Sensitive Data (high 7.5, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2019-0199 and fix it if it is affected. What it is: CVE-2019-0199 is a high-severity denial of service vulnerability in Apache Tomcat, published on 10 Apr 2019. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2019-0199 in the wild and no public exploit code. Affected packages and fixed versions: - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 8.0.0; fixed in 8.5.38 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 8.0.0; fixed in 8.5.38 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 9.0.0; fixed in 9.0.16 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 9.0.0; fixed in 9.0.16 - org.apache.tomcat:tomcat-coyote (Maven): affected from 8.0.0; fixed in 8.5.38 - org.apache.tomcat:tomcat-coyote (Maven): affected from 8.0.0; fixed in 8.5.38 - org.apache.tomcat:tomcat-coyote (Maven): affected from 9.0.0; fixed in 9.0.16 - org.apache.tomcat:tomcat-coyote (Maven): affected from 9.0.0; fixed in 9.0.16 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2019-0199/ (Markdown: https://insights.sbomify.com/CVE-2019-0199/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2019-0199 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-0199 - OSV: https://osv.dev/vulnerability/CVE-2019-0199 --- From sbomify Insights: https://insights.sbomify.com/CVE-2019-0199/ Summaries are generated and may contain mistakes; the official description above is the record.