A flaw was found in JBossWeb in versions before 7.5.31.Final-redhat-3. The fix for CVE-2020-13935 was incomplete in JBossWeb, leaving it vulnerable to a denial of service attack when sending multiple requests with invalid payload length in a WebSocket frame. The highest threat from this vulnerability is to system availability.

The payload length in a WebSocket frame was not correctly validated in Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M1 to 9.0.36, 8.5.0 to 8.5.56 and 7.0.27 to 7.0.104. Invalid payload lengths could trigger an infinite loop. Multiple requests with invalid payload lengths could lead to a denial of service.