CVE-2025-12978

mediumpriority · track · 0EPSS 0.004 · 35 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.41% (35th) EPSS

CVSS 5.4 · medium

Is it mine?

7 products

Check your exposure

Who says so?

6 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

5.4

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.4mediumAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Lsecondary · FSTEC (BDU) RU

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Lsecondary · ENISA EU

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Lsecondaryexploitability 2.8 · impact 2.5

v3.15mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20US

affected products (7)

Products and version ranges known to be affected.

Open Source Fluent Bit <4.1.0all versionscert_bundDE
Open Source Fluent Bit< 4.1.0cert_bundDE
FluentBit Fluent Bit0 → 4.0.12enisa_euvdEU
Treasure Data, Inc. Fluent Bit≤ 4.1.0fstec_bduRU
ООО «Ред Софт» РЕД ОС≤ 8.0fstec_bduRU
treasuredata fluent bit= 4.1.0nvdUScpe:2.3:a:treasuredata:fluent_bit:*:*:*:*:*:*:*:*
Bitnami fluent-bit4.1.0 → 4.1.1osvUSpkg:bitnami/fluent-bit

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2025-2670Fluent Bit: Mehrere SchwachstellenDeutsch2025-11-24csaf · cert_bundDE
Ein entfernter anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Fluent Bit ausnutzen, um Sicherheitsmaßnahmen zu umgehen, beliebigen Code auszuführen, einen Denial-of-Service-Zustand zu verursachen, Daten zu manipulieren und vertrauliche Informationen offenzulegen.
BIT-fluent-bit-2025-12978CVE-2025-129782025-12-01vendor · osvUS
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.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund nvd osv NVD CVE.org MITRE

published 2025-11-24modified 2026-10-08

references (5)

External citations — patches, advisories, analysis.

scry

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