CVE-2020-1938 remediation guide
Apache Tomcat
When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not...
Identify the affected asset
Confirm whether Apache Tomcat is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50, 7.0.0 to 7.0.99, 1.12.0, >= 7.0.0 < 7.0.100, >= 8.5.0 < 8.5.51, >= 9.0.0 < 9.0.31, 30, 31, 32, 6.2.1.0, 9.3.3, 9.3.5, 9.3.6, 8.1.1, 8.2.0, 8.2.1, 10.0.1.4.0, 1.0.1.2, 7.3.3. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Apply updates per vendor instructions.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.