Centrifugal Centrifugo up to 6.8.x Connection handler.go OnClientConnecting headers improper authorization

Summaryinfo

A vulnerability labeled as critical has been found in Centrifugal Centrifugo up to 6.8.x. The affected element is the function OnClientConnecting of the file internal/client/handler.go of the component Connection Handler. Such manipulation of the argument headers leads to improper authorization. This vulnerability is uniquely identified as CVE-2026-71485. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Centrifugal Centrifugo up to 6.8.x and classified as critical. Affected by this issue is the function OnClientConnecting of the file internal/client/handler.go of the component Connection Handler. The manipulation of the argument headers with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Centrifugo is an open-source scalable real-time messaging server. Prior to 6.9.0, Centrifugo copies the client-controlled protocol.ConnectRequest.headers map through OnClientConnecting in internal/client/handler.go, ConnectEvent.Headers, and SetEmulatedHeadersToContext. The requestHeaders path in internal/proxy/http.go, the requestMetadata path in internal/proxy/grpc.go, and the Consume path in internal/unigrpc/grpc.go can forward an allowlisted value as a trusted backend header or metadata value. A remote client can spoof a header such as x-trusted-user for connect, refresh, subscribe, publish, RPC, and related proxy calls when the backend relies on that header for authentication or authorization. The unidirectional gRPC transport has no transport-level HTTP header that can override the emulated value. This issue is fixed in version 6.9.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-71485 since 08/06/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 6.9.0 eliminates this vulnerability.

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Productinfo

Vendor

• Centrifugal

Name

• Centrifugo

Version

• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7
• 6.8

Website

• Product: https://github.com/centrifugal/centrifugo/

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