CVE-2026-54427: Apache bRPC: Stack Exhaustion via Unbounded Recursion in AMF Parser
Uncontrolled recursion in the AMF parser in Apache bRPC < 1.18.0 allows a remote RTMP peer to crash a bRPC process by sending deeply nested AMF objects or arrays. The parser recursively processed nested AMF containers without enforcing a depth limit, which could exhaust the native stack.
Affected Scenarios: Applications using bRPC RTMP support and parsing AMF data from an untrusted RTMP peer. This includes RTMP servers parsing client command messages, RTMP clients parsing server responses or status messages, and either side parsing inbound AMF script data such as metadata or cue points. Direct callers of ReadAMFObject or ReadAMFArray on untrusted input are also affected.
How to Fix: 1. Upgrade Apache bRPC to 1.18.0. 2. Apply the patch from PR https://github.com/apache/brpc/pull/3344 .
Note: The fix introduces a configurable AMF nesting depth limit with default value 128. AMF objects or arrays deeper than amfmaxdepth are rejected after applying the fix.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache bRPCto a version that resolves this vulnerability.Fixed in 1.18.0 - Configuration
Configure the AMF nesting depth limit amf_max_depth to 128; AMF objects or arrays deeper than this limit are rejected.
Apache bRPC AMF parser amf_max_depth = 128