Executive brief
Fluentd is a popular data collection tool used to gather logs and events from various sources. A security flaw in its monitoring component allows sensitive information, such as database passwords, API keys, and cloud credentials, to be exposed through a public web interface. If an attacker can access this interface, they could steal these credentials to gain unauthorized access to other corporate systems and data.
Technical details
The Fluentd Monitor Agent plugin (in_monitor_agent) contains an information disclosure vulnerability due to missing authentication and overly verbose default configurations. The REST API endpoints, specifically /api/plugins.json, include internal instance variables of loaded plugins in their responses. If plugins store sensitive data like passwords or cloud tokens in these variables, they are transmitted in plain text. An unauthenticated attacker with network access to the Monitor Agent port (default 24220) can extract these credentials. The issue is addressed in version 1.19.3 by changing the default visibility of configuration, retry, and debug information to 'false' and restricting query parameter overrides.
Affected products
- Fluent Fluentd < 1.19.3
Timeline
- 2026-06-25: patched: Fix committed and version 1.19.3 released.
- 2026-06-26: advisory: GitHub Security Advisory GHSA-pr7j-96cj-549h published.
- 2026-07-08: disclosed: CVE-2026-44025 published to NVD.