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

published 2022-11-02 4 y ago modified 2026-09-08 2 mo ago also BIT-fluentd-2022-39379 , EUVD-2022-7331 , GHSA-fppq-mj76-fpj2

cvss: 3.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 45.0%; EPSS 45.0% chance of exploitation in 30 days, percentile 98%
public exploits: 0; none known

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`.

Patch / fix

fixed in 3 distros 1 links 1

rubygems fluentd 1.15.3
bitnami fluentd 1.15.3
fluentd fluentd 1.15.3

rubygem-fluentd CBL-Mariner 2.0 1.14.6-2

azure linux advisories AZL-11396

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

github.com/fluent/fluentd@48e5b85 commit

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-39379 updated 2026-06-26 cvss 8.1

fluentd: remote code execution via crafted JSON payloads

Red Hat OpenShift Container Platform 3.11 fluentd, openshift3/ose-logging-fluentd Red Hat OpenStack Platform 13 (Queens) puppet-fluentd, rhosp13/openstack-fluentd
affected: no fix planned “Out of support scope”
Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/fluentd-rhel8
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 18 mo ago (2025-04-23)

Exploit prediction

44.98% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	3.1	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
GitHub	3.1	3.1	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
rubygems	fluentd	>=1.13.2, <1.15.3	1.15.3
bitnami	fluentd	>=1.13.2, <1.15.3	1.15.3

Affected products

fluent fluentd

Classification

Weakness

CWE-502 Deserialization of Untrusted Data

References

github.com /fluent/fluentd/commit/48e5b85dab1b6d4c273090d538fc11b3f2fd8135
web, patch, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/MYD5QV66OLDHES6IKVYYM3Y3YID3VVCO/
vendor-advisory, web
github.com /fluent/fluentd/security/advisories/GHSA-fppq-mj76-fpj2
web, third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2022-39379
advisory, web
github.com /fluent/fluentd
package
github.com /rubysec/ruby-advisory-db/blob/master/gems/fluentd/CVE-2022-39379.yml
web
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/MYD5QV66OLDHES6IKVYYM3Y3YID3VVCO
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary