Information disclosure flaw in Apache Tomcat; patch now

Cybersecurity specialists reported the finding of a severe information disclosure vulnerability in Apache Tomcat, the servlet container developed under the Jakarta project at the Apache Software Foundation. According to the report, exploiting this flaw allows remote attackers to gain access to sensitive information.

Below is a brief description of the reported flaw, in addition to its respective identification key and score according to the Common Vulnerability Scoring System (CVSS).

CVE-2020-13943: The flaw exists due to inappropriate management of internal resources within Apache Tomcat during HTTP/2 request processing. If an HTTP/2 client exceeds the maximum number of concurrent transmissions for a connection (representing a protocol violation), a subsequent request might contain HTTP/2 headers, including pseudo headers from a previous request instead of the expected ones. As a result, users might receive responses for unexpected resources.

This is an average severity flaw that received a CVSS score of 4.6/10, cybersecurity experts mention. 

The vulnerability resides in the following versions of Apache Tomcat: 8.5.0, 8.5.1, 8.5.2, 8.5.3, 8.5.4, 8.5.5, 8.5.6, 8.5.7, 8.5.8, 8.5.9, 8.5.10, 8.5.11, 8.5.12, 8.5.13, 8.5.14, 8.5.15, 8.5.16, 8.5.17, 8.5.18, 8.5.19, 8.5.20, 8.5.21, 8.5.22, 8.5.23, 8.5.24, 8.5.25, 8.5.26, 8.5.27, 8.5.28, 8.5.29, 8.5.30, 8.5.31, 8.5.32, 8.5.33, 8.5.34, 8.5.35, 8.5.36, 8.5.37, 8.5.38, 8.5.39, 8.5.40, 8.5.41, 8.5.42, 8.5.43, 8.5.44, 8.5.45, 8.5.46, 8.5.47, 8.5.48, 8.5.49, 8.5.50, 8.5.51, 8.5.52, 8.5.53, 8.5.54, 8.5.55, 8.5.56, 8.5.57, 9.0.0, 9.0.0-M1, 9.0.0-M2, 9.0.0-M3, 9.0.0-M4, 9.0.0-M5, 9.0.0-M6, 9.0.0-M7, 9.0.0-M8, 9.0.0-M9, 9.0.0-M10, 9.0.0-M11, 9.0.0-M12, 9.0.0-M13, 9.0.0-M14, 9.0.0-M15, 9.0.0-M16, 9.0.0-M17, 9.0.0-M18, 9.0.0-M19, 9.0.0-M20, 9.0.0-M21, 9.0.0-M22, 9.0.0-M23, 9.0.0-M24, 9.0.0-M25, 9.0.0-M26, 9.0.0-M27, 9.0.1, 9.0.2, 9.0.3, 9.0.4, 9.0.5, 9.0.6, 9.0.7, 9.0.8, 9.0.9, 9.0.10, 9.0.11, 9.0.12, 9.0.13, 9.0.14, 9.0.15, 9.0.16, 9.0.17, 9.0.18, 9.0.19, 9.0.20, 9.0.21, 9.0.22, 9.0.23, 9.0.24, 9.0.25, 9.0.26, 9.0.27, 9.0.28, 9.0.29, 9.0.30, 9.0.31, 9.0.32, 9.0.33, 9.0.34, 9.0.35, 9.0.36, 9.0.37, 10.0.0-M1, 10.0.0-M2, 10.0.0-M3, 10.0.0-M4, 10.0.0-M5, 10.0.0-M6, 10.0.0-M7, 10.0.0.0-M1.

While the flaw can be exploited by remote threat actors by sending specially designed requests, experts have not yet detected exploit attempts in real-world scenarios, or the existence of malware associated with this attack.

Apache Foundation has already released the corresponding patches, so users of affected versions should only update as soon as possible.