Vulnerability identifier: #VU29333

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-11996

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Apache Tomcat
Server applications / Web servers

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper management of internal resources with the application when processing HTTP/2 requests. A remote attacker can send specially crafted sequence of HTTP/2 requests to the affected server and trigger high CPU load for several seconds. A large number of such requests causes denial of service.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Tomcat: 10.0.0-M1 - 10.0.0.0-M1, 9.0.0 - 9.0.35, 8.5.0 - 8.5.55

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External links
http://lists.apache.org/thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3E

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.