# CVE-2020-13934: Improper Restriction of Operations within the Bounds of a Memory Buffer in Apache Tomcat - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Fix available:** Yes - **Published:** 14 Jul 2020 - **Updated:** 8 Oct 2026 - **Also known as:** BIT-tomcat-2020-13934, DEBIAN-CVE-2020-13934, GHSA-vf77-8h7g-gghp, UBUNTU-CVE-2020-13934 ## What is CVE-2020-13934? CVE-2020-13934 is a high-severity vulnerability in Apache Tomcat, published on 14 Jul 2020. ### Official description An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56 did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such requests were made, an OutOfMemoryException could occur leading to a denial of service. Weakness: CWE-476 (NULL Pointer Dereference), CWE-401 (Missing Release of Memory after Effective Lifetime) ## Which versions are affected by CVE-2020-13934? 13 open source packages ship an affected version, including org.apache.tomcat:tomcat, tomcat and org.apache.tomcat:tomcat-coyote. It affects 14 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.apache.tomcat:tomcat` | Maven | From 10.0.0-M1 | 10.0.0-M6 | | `org.apache.tomcat:tomcat` | Maven | From 10.0.0-M1 | 10.0.0-M6 | | `org.apache.tomcat:tomcat` | Maven | From 8.5.1 | 8.5.56 | | `org.apache.tomcat:tomcat` | Maven | From 8.5.1 | 8.5.56 | | `org.apache.tomcat:tomcat` | Maven | From 9.0.0.M5 | 9.0.36 | | `org.apache.tomcat:tomcat` | Maven | From 9.0.0.M5 | 9.0.36 | | `tomcat` | Bitnami | From 8.5.1 | 8.5.57, 9.0.37 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 10.0.0-M1 | 10.0.0-M6 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 10.0.0-M1 | 10.0.0-M6 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 8.5.1 | 8.5.56 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 8.5.1 | 8.5.56 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 9.0.0.M5 | 9.0.36 | | `org.apache.tomcat:tomcat-coyote` | Maven | From 9.0.0.M5 | 9.0.36 | Products: Apache Tomcat, Canonical Ubuntu Linux, Debian Debian Linux, Netapp Oncommand System Manager, Opensuse Leap, Oracle Agile Engineering Data Management, Oracle Agile Product Lifecycle Management, Oracle Communications Instant Messaging Server, Oracle Fmw Platform, Oracle Instantis Enterprisetrack, Oracle Managed File Transfer, Oracle Mysql Enterprise Monitor, Oracle Siebel Ui Framework, Oracle Workload Manager. ## How do I fix CVE-2020-13934? Upgrade org.apache.tomcat:tomcat to a fixed version for your release line: 10.0.0-M6, 8.5.56 or 9.0.36. ## Is CVE-2020-13934 being exploited? There is no known exploitation of CVE-2020-13934 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-2020-13934 and fix it if it is affected. What it is: CVE-2020-13934 is a high-severity vulnerability in Apache Tomcat, published on 14 Jul 2020. Exploitation: There is no known exploitation of CVE-2020-13934 in the wild and no public exploit code. Affected packages and fixed versions: - org.apache.tomcat:tomcat (Maven): affected from 10.0.0-M1; fixed in 10.0.0-M6 - org.apache.tomcat:tomcat (Maven): affected from 10.0.0-M1; fixed in 10.0.0-M6 - org.apache.tomcat:tomcat (Maven): affected from 8.5.1; fixed in 8.5.56 - org.apache.tomcat:tomcat (Maven): affected from 8.5.1; fixed in 8.5.56 - org.apache.tomcat:tomcat (Maven): affected from 9.0.0.M5; fixed in 9.0.36 - org.apache.tomcat:tomcat (Maven): affected from 9.0.0.M5; fixed in 9.0.36 - tomcat (Bitnami): affected from 8.5.1; fixed in 8.5.57, 9.0.37 - org.apache.tomcat:tomcat-coyote (Maven): affected from 10.0.0-M1; fixed in 10.0.0-M6 - org.apache.tomcat:tomcat-coyote (Maven): affected from 10.0.0-M1; fixed in 10.0.0-M6 - org.apache.tomcat:tomcat-coyote (Maven): affected from 8.5.1; fixed in 8.5.56 - org.apache.tomcat:tomcat-coyote (Maven): affected from 8.5.1; fixed in 8.5.56 - org.apache.tomcat:tomcat-coyote (Maven): affected from 9.0.0.M5; fixed in 9.0.36 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-2020-13934/ (Markdown: https://insights.sbomify.com/CVE-2020-13934/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-13934 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-13934 - OSV: https://osv.dev/vulnerability/CVE-2020-13934 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-13934/ Summaries are generated and may contain mistakes; the official description above is the record.