Disclosure summary
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.
Source-reported weakness categories
NVD-CWE-noinfo
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2025-12978
Open original source · Updated Oct 08, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
| Vendor | Product / association | Version / bounds |
|---|---|---|
| treasuredata | fluent_bit | 4.1.0 |
Original records & references
- NIST NVD record
- CVE Program record
- fluentbit.io — Release Notes
PUBLISHED 2025-11-24T10:15:46-05:00
MODIFIED 2026-10-08T06:10:00-04:00
INGESTED 2026-10-08T12:35:23-04:00