EUVD-2026-21607
GHSA-q98v-9f9w-f49q
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:N/AU:N/R:U/V:X/RE:L/U:X
Lifecycle Timeline
3Description
The frontend gRPC server's streaming interceptor chain did not include the authorization interceptor. When a ClaimMapper and Authorizer are configured, unary RPCs enforce authentication and authorization, but the streaming AdminService/StreamWorkflowReplicationMessages endpoint accepted requests without credentials. This endpoint is registered on the same port as WorkflowService and cannot be disabled independently. An attacker with network access to the frontend port could open the replication stream without authentication. Data exfiltration is possible, but only when a configured replication target is correctly configured and the attacker has knowledge of the cluster configuration, as the history service validates cluster IDs and peer membership before returning replication data. Temporal Cloud is not affected.
Analysis
Temporal's frontend gRPC server fails to enforce authentication and authorization on the StreamWorkflowReplicationMessages endpoint, allowing unauthenticated network attackers to establish replication streams and potentially exfiltrate workflow data when replication targets are configured. The vulnerability affects Temporal versions prior to 1.28.4, 1.29.6, and 1.30.4; Temporal Cloud deployments are unaffected. …
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