Apache bRPC up to 1.17.x Streaming Parser ParseStreamingMessage missing authentication

Summaryinfo

A vulnerability, which was classified as critical, was found in Apache bRPC up to 1.17.x. This affects the function ParseStreamingMessage of the component Streaming Parser. Executing a manipulation can lead to missing authentication. This vulnerability is tracked as CVE-2026-78334. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Apache bRPC up to 1.17.x. It has been declared as critical. This vulnerability affects the function ParseStreamingMessage of the component Streaming Parser. The manipulation with an unknown input leads to a missing authentication vulnerability. The CWE definition for the vulnerability is CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Missing authentication in the streaming RPC path of Apache bRPC (version < 1.18.0) on all platforms allows a remote attacker to bypass server authentication and inject or deliver streaming frames, when a server is configured with an Authenticator. Root Cause: When authentication is configured, streaming RPC frames are consumed directly by the streaming parser (ParseStreamingMessage) and never pass through InputMessenger's authentication hook, so an unauthenticated peer can exchange frames without being authenticated. In addition, a server-accepted stream is bound lazily to the first frame that happens to carry its id, so a stream could accept a frame carrying its id from a socket other than the socket that created the stream. Affected Scenarios: A bRPC server configured with authentication that serves streaming RPC from an untrusted network, or a deployment where a foreign connection can impersonate a stream by id, can be made to accept unauthorized streaming frames. How to Fix: Upgrade bRPC to 1.18.0, which fixes this issue, or apply the patch in PR https://github.com/apache/brpc/pull/3481. Note: The fix rejects streaming frames on server sockets when configured authentication has not completed, and keeps server-accepted streams bound to the socket of their creating RPC and rejects frames arriving from another socket. Authenticated streaming RPC behavior and the wire format are unchanged; only unauthenticated or foreign-socket frames are now rejected.

The advisory is available at lists.apache.org. This vulnerability was named CVE-2026-78334 since 08/24/2026. 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.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-107186). If you want to get best quality of vulnerability data, you may have to visit VulDB.

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/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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