CVE-2026-5724: Missing Authentication on Streaming gRPC Replication Endpoint

Severity: medium (CVSS 6.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-10 · updated 2026-07-08
Weakness: CWE-306

Description

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. The fix was applied per release line: it is present in 1.28.4, 1.29.6, 1.30.4, 1.31.2, and 1.32.0 and later releases on each line. Releases 1.31.0 and 1.31.1 do not contain the fix and are affected. Temporal Cloud is not affected.

Affected products

Temporal Technologies, Inc. temporal: from 1.24.0 before 1.28.4; from 1.29.0 before 1.29.6; from 1.30.0 before 1.30.4; from 1.31.0 before 1.31.2 — fixed in 1.28.4, 1.29.6, 1.30.4, 1.31.2

How to fix

Upgrade to a fixed version: Temporal Technologies, Inc. temporal 1.28.4, 1.29.6, 1.30.4, 1.31.2. Check the vendor advisory for mitigations.

References

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