CVE-2020-13936 Velocity Sandbox Bypass
High 8.8
Published
Updated
Check this codebase for CVE-2020-13936 and fix it if it is affected.
What it is: CVE-2020-13936 is a high-severity code injection vulnerability in Debian Debian Linux, published on 10 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-13936 in the wild and no public exploit code.
Affected packages and fixed versions:
- org.apache.velocity:velocity (Maven): affected all versions up to 1.7; no fix listed
- org.apache.velocity:velocity (Maven): affected all versions up to 1.7; no fix listed
- org.apache.velocity:velocity-engine-parent (Maven): affected all versions; fixed in 2.3
- org.apache.velocity:velocity-engine-parent (Maven): affected all versions; fixed in 2.3
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-2020-13936/ (Markdown: https://insights.sbomify.com/CVE-2020-13936/index.md)
Attackers can execute arbitrary Java code or system commands by modifying Velocity templates in applications allowing untrusted template uploads.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-13936?
CVE-2020-13936 is a high-severity code injection vulnerability in Debian Debian Linux, published on 10 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An attacker that is able to modify Velocity templates may execute arbitrary Java code or run arbitrary system commands with the same privileges as the account running the Servlet container. This applies to applications that allow untrusted users to upload/modify velocity templates running Apache Velocity Engine versions up to 2.2.
Which versions are affected by CVE-2020-13936?
4 open source packages ship an affected version, including org.apache.velocity:velocity and org.apache.velocity:velocity-engine-parent. It affects 16 products.
| Package | Affected | Fixed in |
|---|---|---|
org.apache.velocity:velocity Maven | All versions to 1.7 | None |
org.apache.velocity:velocity Maven | All versions to 1.7 | None |
org.apache.velocity:velocity-engine-parent Maven | All versions | 2.3 |
org.apache.velocity:velocity-engine-parent Maven | All versions | 2.3 |
Linux distribution packages (36)
maven-doxia SUSE:Enterprise Storage 7.1 | All versions | 2.0.0-150200.4.18.11 |
maven-doxia-sitetools SUSE:Enterprise Storage 7.1 | All versions | 2.0.0-150200.3.18.3 |
maven-invoker SUSE:Enterprise Storage 7.1 | All versions | 3.3.0-150200.3.7.5 |
maven-javadoc-plugin SUSE:Enterprise Storage 7.1 | All versions | 3.11.1-150200.4.21.2 |
maven-plugin-tools SUSE:Enterprise Storage 7.1 | All versions | 3.15.1-150200.3.15.12 |
maven-reporting-api SUSE:Enterprise Storage 7.1 | All versions | 4.0.0-150200.3.10.12 |
maven-surefire SUSE:Enterprise Storage 7.1 | All versions | 3.5.2-150200.3.9.20.12 |
maven-surefire-plugins SUSE:Enterprise Storage 7.1 | All versions | 3.5.2-150200.3.9.20.2 |
plexus-velocity SUSE:Enterprise Storage 7.1 | All versions | 2.1.0-150200.3.10.3 |
velocity-engine-core SUSE:Enterprise Storage 7.1 | All versions | 2.4-150200.5.3.3 |
maven-doxia SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 2.0.0-150200.4.18.11 |
maven-doxia-sitetools SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 2.0.0-150200.3.18.3 |
maven-invoker SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 3.3.0-150200.3.7.5 |
maven-javadoc-plugin SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 3.11.1-150200.4.21.2 |
maven-plugin-tools SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 3.15.1-150200.3.15.12 |
maven-reporting-api SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 4.0.0-150200.3.10.12 |
maven-surefire SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 3.5.2-150200.3.9.20.12 |
maven-surefire-plugins SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 3.5.2-150200.3.9.20.2 |
plexus-velocity SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 2.1.0-150200.3.10.3 |
velocity-engine-core SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 2.4-150200.5.3.3 |
maven-doxia SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.0.0-150200.4.18.11 |
maven-doxia-sitetools SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.0.0-150200.3.18.3 |
maven-invoker SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 3.3.0-150200.3.7.5 |
maven-javadoc-plugin SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 3.11.1-150200.4.21.2 |
maven-plugin-tools SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 3.15.1-150200.3.15.12 |
maven-reporting-api SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 4.0.0-150200.3.10.12 |
maven-surefire SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 3.5.2-150200.3.9.20.12 |
maven-surefire-plugins SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 3.5.2-150200.3.9.20.2 |
plexus-velocity SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.1.0-150200.3.10.3 |
velocity-engine-core SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.4-150200.5.3.3 |
maven-doxia SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 2.0.0-150200.4.18.11 |
maven-doxia-sitetools SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 2.0.0-150200.3.18.3 |
maven-invoker SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 3.3.0-150200.3.7.5 |
maven-javadoc-plugin SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 3.11.1-150200.4.21.2 |
maven-plugin-tools SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 3.15.1-150200.3.15.12 |
maven-reporting-api SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 4.0.0-150200.3.10.12 |
Products include Apache Velocity Engine, Apache Wss4j, Debian Debian Linux, Oracle Banking Deposits and Lines of Credit Servicing, Oracle Banking Enterprise Default Management, Oracle Banking Loans Servicing and 10 more.
How do I fix CVE-2020-13936?
Upgrade to a fixed version.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2020-13936 being exploited?
There is no known exploitation of CVE-2020-13936 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-JU40621, CLSA-2025-1752019387, DEBIAN-CVE-2020-13936, DLA-2595-1, GHSA-59j4-wjwp-mw9m, MGASA-2021-0183 and 9 more.