CVE-2025-12977 json
CVE-2025-12977
published 2025-11-24 11 mo ago modified 2026-10-18 21 d ago also BIT-fluent-bit-2025-12977 , EUVD-2025-198811
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 55%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- bitnami fluent-bit 4.1.1
- FluentBit Fluent Bit 4.0.12
- fluent-bit CBL-Mariner 2.0 3.0.6-6
- fluent-bit Azure Linux 3.0 3.1.10-4
azure linux advisories AZL-71080AZL-71102
Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 11 mo ago
Exploit prediction
0.76% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| OSV | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | fluent-bit | >=4.1.0, <4.1.1 |
4.1.1 |
Affected products
- FluentBit Fluent Bit
Classification
- Weakness
-
- CWE-1287 Improper Validation of Specified Type of Input
References
Sources
- CVE List CVE-2025-12977
- NVD CVE-2025-12977
- OSV BIT-fluent-bit-2025-12977
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.