CVE Catalog

CVE-2026-74757

Low risk· EPSS 15%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.24%

15th percentile - higher than 15% of all known CVEs

Summary

Uncontrolled resource allocation in the mcpack2pb component in Apache bRPC (version < 1.18.0) allows remote attackers to make the server allocate a large amount of memory by sending a crafted mcpack request with a huge array item count. The parser trusts the item count from the header without validating it against the actual payload size, potentially preallocating about 16GB of virtual memory.

Risk Assessment

This can abort the process (SIGABRT) on memory-constrained hosts, causing denial of service.

Recommendation

Upgrade bRPC to version 1.18.0 or apply the patch in PR #3451, which caps the array item count to the remaining bytes of the array payload.

Other vulnerabilities in Apache bRPC

See all
Original NVD description (English source)

Uncontrolled resource allocation in the mcpack2pb component in Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to make the server allocate a large amount of memory via sending a crafted mcpack request with a huge array item count. Root Cause: The bRPC mcpack2pb parser trusts the item count stored in the mcpack array header without validating it against the actual payload size. The code generated by the mcpack2pb protoc plugin uses this count to preallocate memory for repeated protobuf fields via Reserve(). A malformed request declaring item_count = 0x7fffffff can force the server to preallocate about 16GB of virtual memory, which may abort the process (SIGABRT) on memory-constrained hosts. Affected Scenarios: Use a bRPC server that wires a NsheadService to UbrpcMcpack2Adaptor (the Baidu ubrpc deployment pattern) and parses requests with code generated by the mcpack2pb protoc plugin. The request body is parsed before authentication. 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/3451 Note: No matter which option you choose, you should know that the fix caps the array item count to the remaining bytes of the array payload.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS