ClickCease Critical Fluent Bit Vulnerability Affects Major Cloud Providers

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Critical Fluent Bit Vulnerability Affects Major Cloud Providers

Rohan Timalsina

June 4, 2024 - TuxCare expert team

Researchers have identified a critical memory corruption vulnerability in Fluent Bit, a popular logging and metrics utility. Dubbed Linguistic Lumberjack, this flaw exists in Fluent Bit’s embedded HTTP server, specifically in the way it parses trace requests. Attackers can exploit it to cause severe issues such as denial-of-service (DoS), information disclosure, and remote code execution (RCE).


What is Fluent Bit?


Fluent Bit is an open-source tool that can process and forward logs and metrics. It enables users to collect log events or metrics from various sources, process them with features like filtering and SQL stream processing, and deliver them to different backends. It’s known for being fast, lightweight, and well-suited for cloud and containerized environments. Fluent Bit is used by major providers like Microsoft Azure, Google Cloud, and Amazon Web Services (AWS).


Fluent Bit Vulnerability “CVE-2024-4323”


The issue lies within the /api/v1/traces endpoint, designed to handle service uptime, plugin metrics, health checks, and other monitoring activities. The problem arises because the data types of input names are not properly validated during the parsing of incoming requests. By sending non-string values in the input array of a request, an attacker can exploit this weakness to cause memory corruption issues.

The affected versions of Fluent Bit are from 2.0.7 to 3.0.3. The good news is that the vulnerability has been addressed in version 3.0.4. Users are strongly advised to upgrade to this latest version to mitigate the risks. If your organization relies on cloud services that use Fluent Bit, contacting your cloud provider to confirm that they have implemented the necessary updates is essential.




The discovery of the Linguistic Lumberjack vulnerability in Fluent Bit underscores the importance of staying vigilant about software updates and security patches. Even if a specific product vulnerability seems irrelevant to you, its widespread use in critical infrastructure means it can indirectly affect you. By understanding and addressing these vulnerabilities promptly, you can help safeguard your systems and data against potential threats.


The sources for this article include a story from ThreatDown.

Critical Fluent Bit Vulnerability Affects Major Cloud Providers
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Critical Fluent Bit Vulnerability Affects Major Cloud Providers
Learn about the Linguistic Lumberjack vulnerability in Fluent Bit. Explore how it impacts cloud services and how to mitigate the risks.
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