CVE-2021-41186
5.9 · MEDIUMOverview
CVE-2021-41186 is a medium-severity vulnerability affecting fluentd fluentd. It was published on October 29, 2021 and has a CVSS 3.1 base score of 5.9 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Fluentd collects events from various data sources and writes them to files to help unify logging infrastructure. The parser_apache2 plugin in Fluentd v0.14.14 to v1.14.1 suffers from a regular expression denial of service (ReDoS) vulnerability. A broken apache log with a certain pattern of string can spend too much time in a regular expression, resulting in the potential for a DoS attack. This issue is patched in version 1.14.2 There are two workarounds available. Either don't use parser_apache2 for parsing logs (which cannot guarantee generated by Apache), or put patched version of parser_apache2.rb into /etc/fluent/plugin directory (or any other directories specified by the environment variable `FLUENT_PLUGIN` or `--plugin` option of fluentd).
Remediation
Check the references section for vendor advisories and patches from fluentd. Update fluentd to the latest patched version. 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.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| fluentd | fluentd | 0.14.14 | Affected |
References
Frequently Asked Questions
What is CVE-2021-41186?
CVE-2021-41186 is a medium-severity vulnerability affecting fluentd fluentd. It was published on October 29, 2021 and has a CVSS 3.1 base score of 5.9 (MEDIUM).
How severe is CVE-2021-41186?
This vulnerability has a CVSS 3.1 base score of 5.9, 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-2021-41186?
Check the references section for vendor advisories and patches from fluentd. Update fluentd to the latest patched version. 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-2021-41186?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-41186 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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