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.
Weakness
The product dereferences a pointer that it expects to be valid but is NULL.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Fluent_bit | Treasuredata | 3.1.9 (including) | 3.1.9 (including) |