QID 730142

Date Published: 2021-07-19

QID 730142: Apache Tomcat Denial Of Service Vulnerability (CVE-2021-30639)

Apache Tomcat is an open source web server and servlet container developed by the Apache Software Foundation.

A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests.

Affected Versions:
Apache Tomcat 10.0.3 to 10.0.4
Apache Tomcat 9.0.44
Apache Tomcat 8.5.64

QID Detection Logic (Unauthenticated):
The QID checks for vulnerable version by sending a GET /QUALYS730142 HTTP/1.0 request which helps in retrieving the installed version of Apache Tomcat in the banner of the response.

Successful exploitation of the vulnerability can allow an attacker to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability.

  • CVSS V3 rated as High - 7.5 severity.
  • CVSS V2 rated as Medium - 5 severity.
    • Solution
    Upgrade to the Apache Tomcat 10.0.5, 9.0.45, 8.5.65 versions or to the latest version of Apache Tomcat. Please refer to Apache Tomcat Security Advisory.

    Vendor References

    CVEs related to QID 730142

    CVE-2021-30639 |
    Software Advisories
    Advisory ID Software Component Link
    Apache_Tomcat_10.0.5 URL Logo tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.0.5
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