CVE-2025-12977

Critical

Description

Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins fail to sanitize tag_key inputs. An attacker with network access or the ability to write records into Splunk or Elasticsearch can supply tag_key values containing special characters such as newlines or ../ that are treated as valid tags. Because tags influence routing and some outputs derive filenames or contents from tags, this can allow newline injection, path traversal, forged record injection, or log misrouting, impacting data integrity and log routing.

SeverityCritical
CVSS9.1
Exploit probability—
ProductTreasuredata Fluent Bit
PublishedNov 24, 2025
First seenNov 24, 2025
Weakness typeCWE-187CWE-187

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
treasuredata fluent_bit4.1.0—

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CVE-2025-12977 · Treasuredata Fluent Bit · Dark Radar