# CVE-2019-17563: In Apache Tomcat, when using FORM authentication there was a narrow window where an attacker could perform a session fixation attack > An attacker could perform a session fixation attack in Apache Tomcat when using FORM authentication, potentially leading to account takeover. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 23 Dec 2019 - **Updated:** 8 Oct 2026 - **Also known as:** DEBIAN-CVE-2019-17563, GHSA-9xcj-c8cr-8c3c, UBUNTU-CVE-2019-17563 ## What is CVE-2019-17563? CVE-2019-17563 is a high-severity authentication bypass vulnerability in Apache Tomcat, published on 23 Dec 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description When using FORM authentication with Apache Tomcat 9.0.0.M1 to 9.0.29, 8.5.0 to 8.5.49 and 7.0.0 to 7.0.98 there was a narrow window where an attacker could perform a session fixation attack. The window was considered too narrow for an exploit to be practical but, erring on the side of caution, this issue has been treated as a security vulnerability. Weakness: CWE-384 (Session Fixation) ## Which versions are affected by CVE-2019-17563? 6 open source packages ship an affected version, including org.apache.tomcat.embed:tomcat-embed-core. It affects 11 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | All versions | 7.0.99 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | All versions | 7.0.99 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 8.0.0 | 8.5.50 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 8.0.0 | 8.5.50 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 9.0.0 | 9.0.30 | | `org.apache.tomcat.embed:tomcat-embed-core` | Maven | From 9.0.0 | 9.0.30 | Products: Apache Tomcat, Canonical Ubuntu Linux, Debian Debian Linux, Opensuse Leap, Oracle Agile Engineering Data Management, Oracle Hyperion Infrastructure Technology, Oracle Instantis Enterprisetrack, Oracle Micros Relate Crm Software, Oracle Mysql Enterprise Monitor, Oracle Retail Order Broker, Oracle Transportation Management. ## How do I fix CVE-2019-17563? Upgrade org.apache.tomcat.embed:tomcat-embed-core to a fixed version for your release line: 7.0.99, 8.5.50 or 9.0.30. ## Is CVE-2019-17563 being exploited? There is no known exploitation of CVE-2019-17563 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-2019-17563 and fix it if it is affected. What it is: CVE-2019-17563 is a high-severity authentication bypass vulnerability in Apache Tomcat, published on 23 Dec 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2019-17563 in the wild and no public exploit code. Affected packages and fixed versions: - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected all versions; fixed in 7.0.99 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected all versions; fixed in 7.0.99 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 8.0.0; fixed in 8.5.50 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 8.0.0; fixed in 8.5.50 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 9.0.0; fixed in 9.0.30 - org.apache.tomcat.embed:tomcat-embed-core (Maven): affected from 9.0.0; fixed in 9.0.30 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-2019-17563/ (Markdown: https://insights.sbomify.com/CVE-2019-17563/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2019-17563 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-17563 - OSV: https://osv.dev/vulnerability/CVE-2019-17563 --- From sbomify Insights: https://insights.sbomify.com/CVE-2019-17563/ Summaries are generated and may contain mistakes; the official description above is the record.