# ReDoS vulnerability in parser_apache2

Advisory record · `GHSA-hwhf-64mh-r662`

- **Identifiers:** `GHSA-hwhf-64mh-r662` · `BIT-fluentd-2021-41186` · `CVE-2021-41186`
- **State:** Confirmed
- **Severity:** CVSS 5.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 1 Nov 2021
- **Updated:** 8 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 1 Nov 2021, 19:16 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `fluentd` (RubyGems): affected `>=0.14.14, <1.14.2`; fixed in `1.14.2`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.022, the 82nd percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 1 Nov 2021. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-hwhf-64mh-r662](https://github.com/advisories/GHSA-hwhf-64mh-r662)
- [OSV: GHSA-hwhf-64mh-r662](https://osv.dev/vulnerability/GHSA-hwhf-64mh-r662)
- <https://github.com/fluent/fluentd/security/advisories/GHSA-hwhf-64mh-r662>
- <https://nvd.nist.gov/vuln/detail/CVE-2021-41186>
- <https://github.com/fluent/fluentd/commit/5482a3d049dab351de0be68f4b4bc562319d8511>
- <https://github.com/fluent/fluentd>
- <https://github.com/fluent/fluentd/blob/master/CHANGELOG.md#v1142>
- <https://github.com/github/securitylab-vulnerabilities/blob/52dc4a2a828c6dc24231967c2937ad92038184a9/vendor_reports/GHSL-2021-102-fluent-fluentd.md>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/fluentd/CVE-2021-41186.yml>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-hwhf-64mh-r662>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-hwhf-64mh-r662/>. Everything for agents: <https://agentprime.io/llms.txt>.