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.
ReDoS vulnerability in parser_apache2
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-hwhf-64mh-r662 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
fluentdReal-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_PLUGINor--pluginoption of fluentd).
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | fluentd | ≥ 0.14.14&&< 1.14.2 | 1.14.2bundle update fluentd --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-hwhf-64mh-r662 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-hwhf-64mh-r662. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-hwhf-64mh-r662 in your dependencies?
O3 Security finds GHSA-hwhf-64mh-r662 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.