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Critical 9.1Published Nov 24, 2025

CVE-2025-12977Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins fail to sanitize tag_key inputs.

Updated under an hour ago ()

Does this affect you?

It affects treasuredata fluent_bit. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
9.1 CRITICAL (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE)
CWE-1287
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Not given
NVD analysis
Modified
Record last updated
Oct 18, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
treasuredata fluent_bit
treasuredata:fluent_bit
4.1.0
NVD

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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