Incorrect Comparison Affecting fluent/fluent-bit package, versions [,4.1.1)
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Test your applications- Snyk IDSNYK-UNMANAGED-FLUENTFLUENTBIT-14107152
- published26 Nov 2025
- disclosed24 Nov 2025
- creditUnknown
Introduced: 24 Nov 2025
NewCVE-2025-12978 (opens in a new tab)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
Upgrade fluent/fluent-bit to version 4.1.1 or higher.
Overview
Affected versions of this package are vulnerable to Incorrect Comparison due to incorrect key length matching in the tag_key validation logic of the in_http, in_splunk, and in_elasticsearch input plugins. An attacker can manipulate log tags and redirect records to unintended destinations by sending crafted inputs to the affected endpoints, potentially compromising log authenticity, injecting forged data, causing alert flooding, and manipulating routing.