CVE-2025-12977 CVE-2025-12977
Attackers can inject special characters into tag keys to cause path traversal, log misrouting, or record forgery in Fluent Bit input plugins.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-12977?
CVE-2025-12977 is a critical path traversal vulnerability in FluentBit Fluent Bit, published on 24 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-1287
Which versions are affected by CVE-2025-12977?
1 open source package ship an affected version, including fluent-bit. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
fluent-bit Bitnami | From 4.1.0 | 4.1.1 |
Products include Treasuredata Fluent Bit.
How do I fix CVE-2025-12977?
Upgrade fluent-bit to 4.1.1 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2025-12977 being exploited?
There is no known exploitation of CVE-2025-12977 in the wild and no public exploit code.
Other vulnerabilities in FluentBit Fluent Bit
Sources
Also known as AZL-71080, AZL-71102, BIT-fluent-bit-2025-12977, GHSA-v498-rhc6-28g9.