Apache bRPC up to 1.17.x Discovery naming-service reply parser discovery_naming_service.cpp ListDiscoveryNodes out-of-bounds

Summaryinfo

A vulnerability classified as critical was found in Apache bRPC up to 1.17.x. This impacts the function DiscoveryNamingService::GetServers/DiscoveryNames::ListDiscoveryNodes of the file src/brpc/policy/discovery_naming_service.cpp of the component Discovery naming-service reply parser. Executing a manipulation can lead to out-of-bounds. The identification of this vulnerability is CVE-2026-87849. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in Apache bRPC up to 1.17.x. This vulnerability affects the function DiscoveryNamingService::GetServers/DiscoveryNames::ListDiscoveryNodes of the file src/brpc/policy/discovery_naming_service.cpp of the component Discovery naming-service reply parser. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The Discovery naming-service reply parser in Apache bRPC (versions < 1.18.0) calls RapidJSON object-only accessors (FindMember) on JSON values without first validating that those values are objects. A malformed Discovery response whose data/service members or instances list contain non-object entries (e.g. a bare integer) triggers the RapidJSON object-access precondition on the client, reading memory out of bounds and potentially crashing the bRPC client. Root Cause: In src/brpc/policy/discovery_naming_service.cpp, DiscoveryNamingService::GetServers() and DiscoveryNames::ListDiscoveryNodes() access JSON values with member functions on non-object values. RapidJSON only defines these operations for object types; invoking them on a non-object violates the class invariant and results in undefined behavior (out-of-bounds read), commonly crashing the process. Affected Scenarios: An operator-configured (or compromised) Discovery backend returns a malformed /discovery/nodes or /discovery/fetchs response whose data/service/instance entries are not JSON objects, crashing any bRPC client that refreshes its server list. How to Fix: 1. Upgrade bRPC to version 1.18.0 or later, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3533 The fix validates that the Discovery response data, per-service data, and instance entries are JSON objects (and skips non-object node/instance entries and rejects non-object data/service values) before calling member accessors.

The advisory is available at github.com. This vulnerability was named CVE-2026-87849 since 09/09/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/21/2026).

Upgrading to version 1.18.0 eliminates this vulnerability.

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Productinfo

Vendor

• Apache

Name

• bRPC

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17

License

• open-source

Website

• Vendor: https://www.apache.org/
• Product: https://github.com/apache/brpc/

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