fluentd

CVE-2022-39379

CVE-2022-39379 is a low-severity insecure deserialization vulnerability in fluentd (rubygems), affecting versions >= 1.13.2, < 1.15.3. It is fixed in 1.15.3.

Key facts
CVSS score
3.1
Low
Attack vector
Network
Issuing authority
GitHub Advisory Database
Affected package
fluentd
Fixed in
1.15.3
Disclosed
2022

Summary

Impact 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 FLUENTOJOPTIONMODE is explicitly set to object. Please note: The option FLUENTOJOPTIONMODE was introduced in Fluentd version 1.13.2. Earlier versions of Fluentd are not affected by this vulnerability. Patches v1.15.3 Workarounds Do not use FLUENTOJOPTION_MODE=object. References GHSL-2022-067

Impact

What is insecure deserialization?

Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.

Severity and exposure

CVE-2022-39379 has a CVSS score of 3.1 (Low). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.

A fixed version is available (1.15.3). Upgrading removes the vulnerable code path.

Affected versions

rubygems

  • fluentd (>= 1.13.2, < 1.15.3)

Security releases

  • fluentd → 1.15.3 (rubygems)
Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.

Kodem's Application Detection and Response identifies whether CVE-2022-39379 is reachable in your applications. Explore runtime application protection for your team.

See if CVE-2022-39379 is reachable in your applications. Get a demo

Already deployed Kodem? See CVE-2022-39379 in your environment

Remediation advice

Upgrade fluentd to 1.15.3 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently asked questions about CVE-2022-39379

What is CVE-2022-39379?

CVE-2022-39379 is a low-severity insecure deserialization vulnerability in fluentd (rubygems), affecting versions >= 1.13.2, < 1.15.3. It is fixed in 1.15.3. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.

How severe is CVE-2022-39379?

CVE-2022-39379 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of fluentd are affected by CVE-2022-39379?

fluentd (rubygems) versions >= 1.13.2, < 1.15.3 is affected.

Is there a fix for CVE-2022-39379?

Yes. CVE-2022-39379 is fixed in 1.15.3. Upgrade to this version or later.

Is CVE-2022-39379 exploitable, and should I be worried?

Whether CVE-2022-39379 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo

What actually determines whether CVE-2022-39379 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2022-39379?

Upgrade fluentd to 1.15.3 or later.

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