A bug in the error handling of the send file code for the NIO HTTP connector in Apache Tomcat 9.0.0.M1 to 9.0.0.M13, 8.5.0 to 8.5.8, 8.0.0.R

Summary

A bug in the error handling of the send file code for the NIO HTTP connector in Apache Tomcat 9.0.0.M1 to 9.0.0.M13, 8.5.0 to 8.5.8, 8.0.0.RC1 to 8.0.39, 7.0.0 to 7.0.73 and 6.0.16 to 6.0.48 resulted in the current Processor object being added to the Processor cache multiple times. This in turn meant that the same Processor could be used for concurrent requests. Sharing a Processor can result in information leakage between requests including, not not limited to, session ID and the response body. The bug was first noticed in 8.5.x onwards where it appears the refactoring of the Connector code for 8.5.x onwards made it more likely that the bug was observed. Initially it was thought that the 8.5.x refactoring introduced the bug but further investigation has shown that the bug is present in all currently supported Tomcat versions.

Timeline

1. Aug 10, 2017, 10:00 PM UTCCVE published
2. Dec 12, 2023, 9:20 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Nov 14, 2024, 8:02 PM UTCRecord last updated
4. Oct 28, 2026EPSS reached 10%

   FIRST estimates at least a 10% chance of exploitation in the next 30 days

Affected versions

• Apache Software Foundation Apache Tomcat

  9.0.0.M1 to 9.0.0.M13, 8.5.0 to 8.5.8, 8.0.0.RC1 to 8.0.39, 7.0.0 to 7.0.73, 6.0.16 to 6.0.48

• org.apache.tomcat:tomcat-utilMaven

  From 9.0.0.M1 · fixed in 9.0.0.M14

• org.apache.tomcat:tomcat-utilMaven

  From 8.5.0 · fixed in 8.5.9

• org.apache.tomcat:tomcat-utilMaven

  From 8.0.0-RC1 · fixed in 8.0.41

• org.apache.tomcat:tomcat-utilMaven

  From 7.0.0 · fixed in 7.0.75

• org.apache.tomcat:tomcat-utilMaven

  From 6.0.16 · fixed in 6.0.50

References 25