Denial of service in Apache Tomcat

Published: 2021-09-15
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2021-41079
Exploitation vector Network
Public exploit N/A
Vulnerable software
Apache Tomcat
Server applications / Web servers

Vendor Apache Foundation

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Infinite loop

EUVDB-ID: #VU56634

Risk: Medium


CVE-ID: CVE-2021-41079

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No


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

The vulnerability exists due to infinite loop when processing certain TLS packets. A remote attacker can send a specially crafted packet to the application, consume all available system resources and cause denial of service conditions.

Successful exploitation of vulnerability requires that Apache Tomcat is configured to use NIO+OpenSSL or NIO2+OpenSSL for TLS.


Install updates from vendor's website.

Vulnerable software versions

Apache Tomcat: 10.0.0 - 10.0.2, 9.0.0 - 9.0.43, 8.5.0 - 8.5.63

CPE2.3 External links

Q & A

Can this vulnerability be exploited remotely?

How the attacker can exploit this vulnerability?

Is there known malware, which exploits this vulnerability?