# CVE-2025-12977: Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins fail to sanitize tag_key inputs. An attacker with…

Source: https://junglewise.ai/threats/cve-2025-12977-fluent-bit-in-http-in-splunk-and-in-elasticsearch-input-plugins  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-11-24  
License: CC BY 4.0 with a link back

CVE-2025-12977 · Severity: critical · CVSS 9.1 · Published 2025-11-24

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.

Technologies: [Treasuredata Fluent Bit](https://junglewise.ai/threats/technologies/treasuredata-fluent-bit). Vendors: [Treasuredata](https://junglewise.ai/threats/vendors/treasuredata).

## Quick answers

**Is CVE-2025-12977 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-12977 being exploited in the wild.

**How severe is CVE-2025-12977?** Critical severity, with a CVSS score of 9.1, published 24 November 2025.

**Which products and versions are affected?** Treasuredata Fluent Bit. The advisory does not name versions.

**Is there a fix for CVE-2025-12977?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2025-12977?** Check whether you run Treasuredata Fluent Bit. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Treasuredata Fluent Bit

## Related threats

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