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CVE-2021-32749

6.1 · MEDIUM

fail2ban is a daemon to ban hosts that cause multiple authentication errors.

Published Jul 16, 2021CWE-78EPSS 3.62%

Overview

CVE-2021-32749 is a medium-severity vulnerability. It was published on July 16, 2021 and has a CVSS 3.1 base score of 6.1 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.1, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

fail2ban is a daemon to ban hosts that cause multiple authentication errors. In versions 0.9.7 and prior, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2, there is a vulnerability that leads to possible remote code execution in the mailing action mail-whois. Command `mail` from mailutils package used in mail actions like `mail-whois` can execute command if unescaped sequences (`\n~`) are available in "foreign" input (for instance in whois output). To exploit the vulnerability, an attacker would need to insert malicious characters into the response sent by the whois server, either via a MITM attack or by taking over a whois server. The issue is patched in versions 0.10.7 and 0.11.3. As a workaround, one may avoid the usage of action `mail-whois` or patch the vulnerability manually.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/fail2ban/fail2ban/commit/2ed414ed09b3bb4c478abc9366a1ff22024a33c9GitHubgithub.com/fail2ban/fail2ban/commit/410a6ce5c80dd981c22752da034f2529b5eee844GitHubgithub.com/fail2ban/fail2ban/security/advisories/GHSA-m985-3f3v-cwmmReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5WHJK2X2MR2WDYZMCW7COZXJDUSDYMY6/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZRYQ77MTX5WSV33VCJLK4KBKR55QZ7ZA/Refsecurity.gentoo.org/glsa/202310-13GitHubgithub.com/fail2ban/fail2ban/commit/2ed414ed09b3bb4c478abc9366a1ff22024a33c9GitHubgithub.com/fail2ban/fail2ban/commit/410a6ce5c80dd981c22752da034f2529b5eee844GitHubgithub.com/fail2ban/fail2ban/security/advisories/GHSA-m985-3f3v-cwmmReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5WHJK2X2MR2WDYZMCW7COZXJDUSDYMY6/

How CyberStrike helps

Frequently asked questions

What is CVE-2021-32749?

CVE-2021-32749 is a medium-severity vulnerability. It was published on July 16, 2021 and has a CVSS 3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2021-32749?

This vulnerability has a CVSS 3.1 base score of 6.1, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-32749?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-32749?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-32749 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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