CVE-2025-12978

published 2025-11-24

CVE-2025-12978: Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins contain a flaw in the tag_key validation logic that fails to enforce exact key-length…

Priority P4 33 medium 5.4 CVSS 3.1

AV N AC L PR L UI N S U C N I L A L

Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins contain a flaw in the tag_key validation logic that fails to enforce exact key-length matching. This allows crafted inputs where a tag prefix is incorrectly treated as a full match. A remote attacker with authenticated or exposed access to these input endpoints can exploit this behavior to manipulate tags and redirect records to unintended destinations. This compromises the authenticity of ingested logs and can allow injection of forged data, alert flooding and routing manipulation.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
fluentbit	fluent_bit	< 4.0.12	4.0.12
treasuredata	fluent_bit	—	—

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