CVE-2025-12969Network attack vector

Unauthenticated log injection via skipped credential checks

Published Nov 24, 2025 · Updated Nov 24, 2025

Authentication bypass in Fluent Bit 4.1.0 allows remote attackers to inject log records through an exposed Forward input. The in_forward plugin accepts connections without checking configured security.users credentials when no shared_key is set. Exposure requires network access to the Forward listener and the Security.Users-only configuration; accepted records can forge telemetry and alter downstream routing or alerts.

CVSS severity6.5
Medium
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Fluent Bit 4.1.0 allows remote attackers to inject log records through an exposed Forward input. The in_forward plugin accepts connections without checking configured security.users credentials when no shared_key is set. Exposure requires network access to the Forward listener and the Security.Users-only configuration; accepted records can forge telemetry and alter downstream routing or alerts.

The record

CVE
CVE-2025-12969
Published
Nov 24, 2025
Updated
Nov 24, 2025
Vendor
Fluent Bit
Product
Fluent Bit
Classifications
CWE-306, T1565.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fluent Bit · Fluent Bitversion=4.1.0

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1565.002Transmitted Data Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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