Treasuredata: >> Fluent Bit Security Vulnerabilities
Fluent Bit in_forward input plugin does not properly enforce the security.users authentication mechanism under certain configuration conditions. This allows remote attackers with network access to the Fluent Bit instance exposing the forward input to send unauthenticated data. By bypassing authentication controls, attackers can inject forged log records, flood alerting systems, or manipulate routing decisions, compromising the authenticity and integrity of ingested logs.
CVSS Score
6.5
EPSS Score
0.001
Published
2025-11-24
The extract_name function in Fluent Bit in_docker input plugin copies container names into a fixed size stack buffer without validating length. An attacker who can create containers or control container names, can supply a long name that overflows the buffer, leading to process crash or arbitrary code execution.
CVSS Score
8.8
EPSS Score
0.001
Published
2025-11-24
Fluent Bit out_file plugin does not properly sanitize tag values when deriving output file names. When the File option is omitted, the plugin uses untrusted tag input to construct file paths. This allows attackers with network access to craft tags containing path traversal sequences that cause Fluent Bit to write files outside the intended output directory.
CVSS Score
5.3
EPSS Score
0.001
Published
2025-11-24
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 Score
9.1
EPSS Score
0.001
Published
2025-11-24
Fluent Bit in_http, in_splunk, and in_elasticsearch input plugins contain a flaw in the tag_key validation logic that fails to enforce exact key-length matching. This allows crafted inputs where a tag prefix is incorrectly treated as a full match. A remote attacker with authenticated or exposed access to these input endpoints can exploit this behavior to manipulate tags and redirect records to unintended destinations. This compromises the authenticity of ingested logs and can allow injection of forged data, alert flooding and routing manipulation.
CVSS Score
5.4
EPSS Score
0.001
Published
2025-11-24
An issue was discovered in Fluent Bit 3.1.9. When the Prometheus Remote Write input plugin is running and listening on an IP address and port, one can send a packet with Content-Length: 0 and it crashes the server. Improper handling of the case when Content-Length is 0 allows a user (with access to the endpoint) to perform a remote Denial of service attack. The crash happens because of a NULL pointer dereference when 0 (from the Content-Length) is passed to the function cfl_sds_len, which in turn tries to cast a NULL pointer into struct cfl_sds. This is related to process_payload_metrics_ng() at prom_rw_prot.c.
CVSS Score
7.5
EPSS Score
0.005
Published
2025-02-18
An issue was discovered in Fluent Bit 3.1.9. When the OpenTelemetry input plugin is running and listening on an IP address and port, one can send a packet with Content-Length: 0 and it crashes the server. Improper handling of the case when Content-Length is 0 allows a user (with access to the endpoint) to perform a remote Denial of service attack. The crash happens because of a NULL pointer dereference when 0 (from the Content-Length) is passed to the function cfl_sds_len, which in turn tries to cast a NULL pointer into struct cfl_sds. This is related to process_payload_traces_proto_ng() at opentelemetry_prot.c.
CVSS Score
7.5
EPSS Score
0.005
Published
2025-02-18
A memory corruption vulnerability in Fluent Bit versions 2.0.7 thru 3.0.3. This issue lies in the embedded http server’s parsing of trace requests and may result in denial of service conditions, information disclosure, or remote code execution.
CVSS Score
9.8
EPSS Score
0.845
Published
2024-05-20
In Fluent Bit 2.1.8 through 2.2.1, a NULL pointer dereference can be caused via an invalid HTTP payload with the content type of x-www-form-urlencoded. It crashes and does not restart. This could result in logs not being delivered properly.
CVSS Score
7.5
EPSS Score
0.007
Published
2024-03-26
fluent-bit 2.2.2 contains a Use-After-Free vulnerability in /fluent-bit/plugins/custom_calyptia/calyptia.c.
CVSS Score
7.5
EPSS Score
0.001
Published
2024-02-26
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