How severe is CVE-2022-39379?

CVE-2022-39379 has a CVSS score of 3.1/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2022-39379?

CVE-2022-39379 affects the following packages: fluentd (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2022-39379?

Update fluentd to 1.15.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-39379 is resolved across your whole dependency graph.

How do I detect CVE-2022-39379 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fluentd. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2022-39379 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2022-39379?

O3 pinpoints whether CVE-2022-39379 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2022-39379 actively exploited in the wild?

No public exploit code has been indexed for CVE-2022-39379 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2022-39379?

CVE-2022-39379 has an EPSS (Exploit Prediction Scoring System) score of 44.7%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2022-39379?

CVE-2022-39379 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2022-39379 published, and has it been updated?

CVE-2022-39379 was published on November 2, 2022 and was last updated on April 2, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

CVE-2022-39379

LOW

Fluentd vulnerable to remote code execution due to insecure deserialization (in non-default configuration)

Also known asBIT-fluentd-2022-39379GHSA-fppq-mj76-fpj2

Published

Nov 2, 2022

Updated

Apr 2, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

44.7%probability of exploitation in next 30 days

High Risk99th percentile+38.70%

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.

Blast Radius

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

Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on. A remote code execution (RCE) vulnerability in non-default configurations of Fluentd allows unauthenticated attackers to execute arbitrary code via specially crafted JSON payloads. Fluentd setups are only affected if the environment variable FLUENT_OJ_OPTION_MODE is explicitly set to object. Please note: The option FLUENT_OJ_OPTION_MODE was introduced in Fluentd version 1.13.2. Earlier versions of Fluentd are not affected by this vulnerability. This issue was patched in version 1.15.3. As a workaround do not use FLUENT_OJ_OPTION_MODE=object.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`fluentd`	≥ 1.13.2&&< 1.15.3	1.15.3

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fluentd. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update fluentd to 1.15.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-39379 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 pinpoints whether CVE-2022-39379 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2022-39379. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on. A remote code execution (RCE) vulnerability in non-default configurations of Fluentd allows unauthenticated attackers to execute arbitrary code via specially crafted JSON payloads. Fluentd setups are only affected if the environment variable `FLUENT_OJ_OPTION_MODE` is explicitly set to `object`. Please note: The option FLUENT_OJ_OPTION_MODE was introduced in Fluentd version 1.13.2. Earlier versions of Fluentd are not affected by this vulnerability. This issue was patched in v

O3 Security · Impact-Aware SCA

Is CVE-2022-39379 in your dependencies?

O3 detects CVE-2022-39379 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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