What is CVE-2025-12969?

CVE-2025-12969 is a medium-severity vulnerability in Fluentbit Fluent Bit, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2025-11-24.

How severe is CVE-2025-12969?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Fluentbit Fluent Bit

CVE-2025-12969

Fluent Bit in_forward input plugin does not properly enforce the security.users authentication mechanism under certain configuration conditions. This allows remote attackers with network access to the Fluent Bit instance exposing the forward input to send unauthenticated data. By bypassing authentication controls, attackers can inject forged log records, flood alerting systems, or manipulate routing decisions, compromising the authenticity and integrity of ingested logs.

Vulnerability class: Broken Authentication

EPSS: 0.006 (46.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

Fluentbit Fluent Bit — versions 0
Treasuredata Fluent_bit — versions 4.1.0

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

Frequently asked questions

What is CVE-2025-12969?: CVE-2025-12969 is a medium-severity vulnerability in Fluentbit Fluent Bit, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2025-11-24.
How severe is CVE-2025-12969?: Medium severity. CVSS v3 base score is 6.5 out of 10.