# CVE-2021-41186: ReDoS vulnerability in parser_apache2

Source: https://junglewise.ai/threats/cve-2021-41186-redos-vulnerability-in-parser-apache2  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-01  
License: CC BY 4.0 with a link back

CVE-2021-41186 · Severity: low · CVSS 3.1 · Published 2021-11-01

ReDoS vulnerability in parser_apache2

Technologies: [fluentd (RubyGems)](https://junglewise.ai/threats/technologies/fluentd). Vendors: [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2021-41186 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-41186 being exploited in the wild.

**How severe is CVE-2021-41186?** Low severity, with a CVSS score of 3.1, published 1 November 2021.

**Which products and versions are affected?** fluentd (RubyGems) ECOSYSTEM:introduced=0.14.14,fixed=1.14.2.

**Is there a fix for CVE-2021-41186?** Yes. fluentd (RubyGems): upgrade to 1.14.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-41186?** Check whether you run fluentd (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- fluentd (RubyGems): upgrade to 1.14.2 or later

  ```sh
  bundle update fluentd
  ```


## Affected products

- fluentd (RubyGems) ECOSYSTEM:introduced=0.14.14,fixed=1.14.2

## Identifiers

- CVE-2021-41186
- GHSA-hwhf-64mh-r662

## Related threats

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- [Fluent Fluentd denial of service via decompression bomb in input plugins](https://junglewise.ai/threats/cve-2026-44160-fluent-fluentd-denial-of-service-via-decompression-bomb-in-input)
- [Fluent Fluentd information disclosure in Monitor Agent plugin](https://junglewise.ai/threats/cve-2026-44025-fluent-fluentd-information-disclosure-in-monitor-agent-plugin)
- [Fluent Fluentd path traversal in ${tag} placeholder](https://junglewise.ai/threats/cve-2026-44024-fluent-fluentd-path-traversal-in-tag-placeholder)
- [fluentd vulnerable to remote code execution due to insecure deserialization (in non-default configuration)](https://junglewise.ai/threats/cve-2022-39379-fluentd-vulnerable-to-remote-code-execution-due-to-insecure)