NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
💎
💎 RubyGems
Not in CISA KEV
MEDIUM severity

ReDoS vulnerability in parser_apache2GHSA-hwhf-64mh-r662

MEDIUMFix: fluent/fluentd@5482a3d

GHSA-hwhf-64mh-r662 is a medium-severity (CVSS 5.9) Uncontrolled Resource Consumption vulnerability in fluentd. A fix is available for fluentd — see the affected versions and patch details below.

Also known asBIT-fluentd-2021-41186CVE-2021-41186
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs83th percentile — riskier than 83% of all scored CVEsHighest risk
0.00%0.91%1.82%2.73%0.5%2.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
💎fluentd

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

v1.14.2

Workarounds

Either of the following:

  • Don't use parser_apache2 for parsing logs which cannot guarantee generated by Apache.
  • 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).

References

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsfluentd≥ 0.14.14&&< 1.14.21.14.2bundle update fluentd --conservative

Affected Products

1 product · 1 configurations
Application
fluentdfluentd
≥ 0.14.14 && ≤ 1.14.1
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fluentd, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update fluentd to 1.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hwhf-64mh-r662 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact 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. ### Patches v1.14.2 ### Workarounds Either of the following: * Don't use parser_apache2 for parsing logs which cannot guarantee generated by Apache. * Put patched version of parser_apache2.rb into /etc/fluent/plugin directory (or any other directories specified by the environment variable `FLUENT_PLUGIN` or `
O3 Security · Impact-Aware SCA

Is GHSA-hwhf-64mh-r662 in your dependencies?

Find it across RubyGems, including transitive dependencies.

Scan my dependencies How O3 SCA works
ReDoS vulnerability in parser_apache2 (Medium 5.9)