Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M
CVE-2026-44024Fluentd: Remote Code Execution (RCE) via Arbitrary File Write in `${tag}` Placeholder
Critical 9.8
In plain English
A critical-severity path traversal in fluentd from fluent. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on. Prior to 1.19.3, Fluentd allows dynamically constructing file paths using the ${tag} placeholder, and insufficient validation of ${tag} in file configurations such as the path parameter of the out_file plugin allows attackers sending untrusted tags containing path traversal characters to write or overwrite arbitrary files and potentially achieve remote code execution. This issue is fixed in version 1.19.3.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| RubyGems | fluentd | 1.19.3 | GHSA-44hj-4m45-frj3 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://github.com/fluent/fluentd/security/advisories/GHSA-44hj-4m45-frj3 x_refsource_CONFIRM
- https://github.com/fluent/fluentd/pull/5391 x_refsource_MISC
- https://github.com/fluent/fluentd/commit/45c87a81f3ac0b72b3f9dcfe8cfb5f9038f81437 x_refsource_MISC
- https://github.com/fluent/fluentd/releases/tag/v1.19.3 x_refsource_MISC