Is CVE-2025-12977 actively exploited?

No active exploitation of CVE-2025-12977 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2025-12977 be exploited remotely?

Yes. CVE-2025-12977 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2025-12977?

CVE-2025-12977 has a CVSS score of 9.1 (CRITICAL).

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CRITICAL

CVE-2025-12977

CWE-1287Published: November 24, 2025· Updated: Jun 17, 2026

9.1

CVSS v3.1

Official 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.

NVD Source

Risk Analysis

This critical vulnerability in Fluent Bit's in_http, in_splunk, and in_elasticsearch input plugins allows for improper sanitization of tag_key inputs. An attacker can inject special characters, leading to newline injection, path traversal, forged record injection, or log misrouting. With a CVSS score of 9.1, this flaw poses a high risk to data integrity and log routing systems.

No public exploit is currently known for this vulnerability. However, it is remotely exploitable over the network with low attack complexity, requiring only network access or the ability to write records into Splunk or Elasticsearch.

Recommended Action

Users of Treasure Data Fluent Bit version 4.1.0 should apply vendor patches to address the input sanitization issue. Implement robust input validation for tag_key values in all affected input plugins to prevent the injection of special characters.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2025-12977 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 9.1.