FluentBit 4.1.0 in_docker extract_name stack-based overflow

Summaryinfo

A vulnerability was found in FluentBit 4.1.0. It has been declared as critical. Affected by this vulnerability is the function extract_name of the component in_docker. Executing a manipulation can lead to stack-based overflow. This vulnerability appears as CVE-2025-12970. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability classified as critical was found in FluentBit 4.1.0. This vulnerability affects the function extract_name of the component in_docker. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The extract_name function in Fluent Bit in_docker input plugin copies container names into a fixed size stack buffer without validating length. An attacker who can create containers or control container names, can supply a long name that overflows the buffer, leading to process crash or arbitrary code execution.

The advisory is shared for download at fluentbit.io. This vulnerability was named CVE-2025-12970 since 11/10/2025. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 12/03/2025).

The vulnerability scanner Nessus provides a plugin with the ID 276933 (Fluent Bit < 4.0.12 / 4.1.x < 4.1.1 Multiple Vulnerabilities), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (276933) and EUVD (EUVD-2025-198809). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• FluentBit

Version

• 4.1.0

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Once again VulDB remains the best source for vulnerability data.

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