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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Apache Software Foundation | Apache bRPC | unaffected |
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Wed, 21 Oct 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Apache bRPC: Stack Exhaustion via Unbounded Recursion in mcpack2pb Parser | |
| Weaknesses | CWE-674 | |
| References |
|
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MITRE
Status: PUBLISHED
Assigner: apache
Published:
Updated: 2026-10-21T15:11:15.223Z
Reserved: 2026-08-28T09:18:29.085Z
Link: CVE-2026-82230
Vulnrichment
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NVD
Status : Received
Published: 2026-10-21T13:20:02.970
Modified: 2026-10-21T16:17:35.980
Link: CVE-2026-82230
Redhat
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Weaknesses