CVE-2016-8745 Concurrent Execution using Shared Resource with Improper Synchronization in Apache Tomcat
An attacker can exploit a concurrency bug in the NIO connector to leak sensitive data like session IDs and response bodies between requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2016-8745?
CVE-2016-8745 is a high-severity vulnerability in Apache Tomcat, published on 10 Aug 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-388
Which versions are affected by CVE-2016-8745?
10 open source packages ship an affected version, including org.apache.tomcat:tomcat-util. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.apache.tomcat:tomcat-util Maven | From 6.0.16 | 6.0.50 |
org.apache.tomcat:tomcat-util Maven | From 6.0.16 | 6.0.50 |
org.apache.tomcat:tomcat-util Maven | From 7.0.0 | 7.0.75 |
org.apache.tomcat:tomcat-util Maven | From 7.0.0 | 7.0.75 |
org.apache.tomcat:tomcat-util Maven | From 8.0.0-RC1 | 8.0.41 |
org.apache.tomcat:tomcat-util Maven | From 8.0.0-RC1 | 8.0.41 |
4 more packages
org.apache.tomcat:tomcat-util Maven | From 8.5.0 | 8.5.9 |
org.apache.tomcat:tomcat-util Maven | From 8.5.0 | 8.5.9 |
org.apache.tomcat:tomcat-util Maven | From 9.0.0.M1 | 9.0.0.M14 |
org.apache.tomcat:tomcat-util Maven | From 9.0.0.M1 | 9.0.0.M14 |
Products include Apache Tomcat.
How do I fix CVE-2016-8745?
Upgrade org.apache.tomcat:tomcat-util to a fixed version for your release line: 6.0.50, 7.0.75, 8.0.41 or 8.5.9.
Is CVE-2016-8745 being exploited?
There is no known exploitation of CVE-2016-8745 in the wild and no public exploit code.
Other vulnerabilities in Apache Tomcat
Sources
Also known as DLA-779-1, DSA-3754-1, DSA-3755-1, GHSA-w3j5-q8f2-3cqq, MGASA-2017-0050, UBUNTU-CVE-2016-8745.