CVE WatchAug 25, 2026

CVE-2020-1938

Apache Tomcat Improper Privilege Management Vulnerability

CVSS

9.8

Critical

EPSS

99.3%

p100

KEV

YES

Mar 3, 2022

Exploit Today

0-100

Published: Feb 24, 2020 · Last modified: Aug 25, 2026

EPSS · 30d

99.3%EPSS · 30 days99.3%

2026-08-022026-08-30

KEV catalog record

Product

Apache / Tomcat

Vulnerability

Apache Tomcat Improper Privilege Management Vulnerability

Added to KEV

Mar 3, 2022

Remediate by

Mar 17, 2022

Known ransomware use

Summary description

Apache Tomcat treats Apache JServ Protocol (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.

Required action

Apply updates per vendor instructions.

Notes

https://nvd.nist.gov/vuln/detail/CVE-2020-1938

Technical description

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 required. This vulnerability report identified a mechanism that allowed: - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.

Official references

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