CVE-2020-13934
HighCVSS 7.5Exploitation Probability (EPSS)
Very high risk99th percentile - higher than 99% of all known CVEs
Summary
In Apache Tomcat versions 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56, an h2c direct connection did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such requests were made, an OutOfMemoryException could occur leading to a denial of service.
Risk Assessment
An attacker can overload the server, causing memory exhaustion and service unavailability.
Recommendation
Upgrade Apache Tomcat to a version that includes the fix (e.g., 9.0.37, 8.5.57 or later).
Original NVD description (English source)
An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56 did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such requests were made, an OutOfMemoryException could occur leading to a denial of service.