How severe is CVE-2025-12977?

CVE-2025-12977 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2025-12977 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-12977?

CVE-2025-12977 affects Treasuredata Fluent Bit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-12977?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-12977 have an EU (EUVD) identifier?

Yes. CVE-2025-12977 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198811.

When was CVE-2025-12977 published?

CVE-2025-12977 was published on 2025-11-24 and last updated on 2026-06-17.

CVE-2025-12977

CVE-2025-12977 is a critical-severity vulnerability in Treasuredata Fluent Bit with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1287.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-198811
Weakness: CWE-1287
Affected product: Treasuredata Fluent Bit
Published: 2025-11-24
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-12977?: 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.
How severe is CVE-2025-12977?: CVE-2025-12977 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2025-12977 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-12977?: CVE-2025-12977 affects Treasuredata Fluent Bit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-12977?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-12977 have an EU (EUVD) identifier?: Yes. CVE-2025-12977 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198811.
When was CVE-2025-12977 published?: CVE-2025-12977 was published on 2025-11-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:treasuredata:fluent_bit:4.1.0:*:*:*:*:*:*:*

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