CVE-2026-82230 Apache bRPC: Stack Exhaustion via Unbounded Recursion in mcpack2pb Parser
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-82230?
CVE-2026-82230 is a high-severity vulnerability in Apache bRPC, published on 21 Oct 2026.
Official description
Uncontrolled recursion in the mcpack2pb component in Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to make the server crash via sending deeply nested mcpack data.
Root Cause: The bRPC mcpack2pb parser (used to serve nshead_mcpack / ubrpc / public_pbrpc requests) recursively parses nested objects and arrays without any depth limit. For a protobuf message that references itself (e.g. a repeated message field), the generated parser recurses once per nesting level of the incoming mcpack object. A deeply nested request makes the recursion grow unbounded, overflow the stack and crash the process.
Affected Scenarios: Use bRPC server with a recursive-schema protobuf message to serve nshead_mcpack / ubrpc / public_pbrpc requests from untrusted network.
How to Fix: (Choose one of the following options) 1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3499
Note: No matter which option you choose, you should know that the fix enforces the documented parsing depth limit MAX_DEPTH (128) on the parse path, the same limit the serializer already applies. If your requests contain mcpack messages nested deeper than 128 levels, the request will be failed after applying the fix.
Weakness: CWE-674
Which versions are affected by CVE-2026-82230?
How do I fix CVE-2026-82230?
No fix has been published for CVE-2026-82230 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-82230 being exploited?
There is no known exploitation of CVE-2026-82230 in the wild and no public exploit code.
Sources
Also known as GHSA-5pph-8c9p-w8p3.