CVE-2026-5724 Missing Authentication on Streaming gRPC Replication Endpoint
An attacker with network access can bypass authentication on the streaming replication endpoint to potentially exfiltrate data if replication is configured.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-5724?
CVE-2026-5724 is a medium-severity missing authorization vulnerability in temporal, published on 10 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-306
Which versions are affected by CVE-2026-5724?
7 open source packages ship an affected version, including go.temporal.io/server.
| Package | Affected | Fixed in |
|---|---|---|
go.temporal.io/server Go | All versions | 1.28.4, 1.29.6, 1.30.4 |
go.temporal.io/server Go | All versions | 1.28.4 |
go.temporal.io/server Go | All versions | 1.28.4 |
go.temporal.io/server Go | From 1.29.0-135.0 | 1.29.6 |
go.temporal.io/server Go | From 1.29.0-135.0 | 1.29.6 |
go.temporal.io/server Go | From 1.30.0-143.0 | 1.30.4 |
1 more packages
go.temporal.io/server Go | From 1.30.0-143.0 | 1.30.4 |
How do I fix CVE-2026-5724?
Upgrade go.temporal.io/server to a fixed version for your release line: 1.28.4, 1.29.6 or 1.30.4.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-5724 being exploited?
There is no known exploitation of CVE-2026-5724 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as CLEANSTART-2026-AW40978, CLEANSTART-2026-ED75868, CLEANSTART-2026-HK90516, ECHO-0bd4-bfde-70a9, GHSA-q98v-9f9w-f49q, GO-2026-5578 and 8 more.