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TI-2025-11879 Aliases CVE-2025-12969GHSA-2949-r76x-4vc4

Missing authentication in FluentBit Fluent Bit

Priority LOW 36CWE-306Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-306.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00631 50th percentileScored 2026-11-07
Fix Fixed Fluent Bit (FluentBit): 4.0.13

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FluentBitFluent Bitbefore 4.0.134.0.13Patch availableCNA
  • Fluent Bit VendorFluentBit Affected before 4.0.13 Fixed in 4.0.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:treasuredata:fluent_bit:4.1.0:*:*:*:*:*:*:*4.1.0VulnerableFluentBit
  • cpe:2.3:a:treasuredata:fluent_bit:4.1.0:*:*:*:*:*:*:* Versions 4.1.0 Vulnerable ·FluentBit

Remediation

  • Fix · CNA Fluent Bit (FluentBit) Fixed in 4.0.13

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-12969
  2. 2026-10-03 Alias added: GHSA-2949-r76x-4vc4
  3. 2026-10-27 EPSS moved to the 50th–90th percentile

References

Other 2

  • TI-2024-17419 fluent-bit 2.2.2 contains a Use-After-Free vulnerability in /fluent-bit/plugins/custom_calyptia/calyptia.c. CVSS 3.1HIGH 7.5
  • TI-2024-15728 In Fluent Bit 2.1.8 through 2.2.1, a NULL pointer dereference can be caused via an… CVSS 3.1HIGH 7.5
  • TI-2024-04026 Fluent Bit Memory Corruption Vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2021-21547 An issue was discovered in Treasure Data Fluent Bit 1.7.1, a wrong variable is used to… CVSS 3.1HIGH 7.8
  • TI-2021-21546 An issue was discovered in Treasure Data Fluent Bit 1.7.1, erroneous parsing in… CVSS 3.1HIGH 7.8
  • TI-2025-21098 An issue in fluent-bit v.3.7.2 allows a local attacker to cause a denial of service via… CVSS 3.1MEDIUM 5.5
See all 17 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences