Vulnerability identifier: #VU55422

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-30639

CWE-ID: CWE-755

Exploitation vector: Network

Exploit availability: No

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 error management within the application when handling unexpected connection termination. A remote attacker can drop connection with the Apache Tomcat server, which triggers a non-blocking I/O error and causes all requests, handled by that request object, to fail. As a result, a remote attacker can initiate and drop connections to the server and perform a denial of service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Tomcat: 10.0.0 - 10.0.4, 9.0.0 - 9.0.44, 8.5.0 - 8.5.64

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External links
http://lists.apache.org/thread.html/rd84fae1f474597bdf358f5bdc0a5c453c507bd527b83e8be6b5ea3f4%40%3Cannounce.tomcat.apache.org%3E
http://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf@%3Cusers.tomcat.apache.org%3E
http://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf@%3Cdev.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.