CVE-2026-5724

Missing Authentication on Streaming gRPC Replication Endpoint

Published Apr 10, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed

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.

Analysis

Technical impact

The frontend gRPC server’s streaming interceptor chain omitted the authorization interceptor. When ClaimMapper and Authorizer are configured, unary RPCs enforce authentication and authorization, but the streaming AdminService/StreamWorkflowReplicationMessages endpoint accepts requests without credentials. The 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 only when a replication target is correctly configured and the attacker knows the cluster configuration, as the history service validates cluster IDs and peer membership before returning replication data.

Affected Systems

Executables from Temporal Technologies, Inc. marked as temporal are impacted. Any deployment of Temporal that includes a replication target and uses the default streaming replication endpoint is vulnerable until an update is applied. The patch versions listed in the advisory – specifically v1.28.4, v1.29.6, v1.30.4, v1.31.2, and any release 1.32.0 or newer – have addressed the issue, but releases 1.31.0 and 1.31.1 remain affected.

Risk and Exploitability

Vulnerability involves an unauthorized replication stream endpoint that bypasses authentication. The CVSS score of 6.3 indicates moderate severity. EPSS indicates a very low exploitation probability, and the vulnerability is not listed in the CISA KEV catalog, suggesting it is not actively exploited at scale. The likely attack vector is a malicious actor who can reach the Temporal frontend gRPC port, which is often exposed to internal or compromised networks. Exploitation also mandates knowledge of the replication target; therefore, risk is higher in environments where replication is enabled and not properly isolated. Temporal Cloud deployments are not affected.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Temporal Technologies, Inc.

temporal

unaffected

Version	Status	Constraints
`1.24.0`	affected	< 1.28.4
`1.29.0`	affected	< 1.29.6
`1.30.0`	affected	< 1.30.4
`1.31.0`	affected	< 1.31.2

No data.

Vendor Product Versions

Temporal

Version	Status	Scheme	Platform
`[1.24.0,1.30.3]`	affected	semver	—
`[1.24.0,1.29.5]`	affected	semver	—
`[1.24.0,1.28.3]`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Temporal to a patched release (v1.28.4 or later) that includes the missing authentication fix
Restrict network access to the Temporal frontend gRPC port to limit attacker reach
Ensure replication targets are only configured for trusted clusters and that cluster IDs and peer membership checks are correctly enforced
Enable monitoring for unexpected replication stream activity and audit replication logs for unauthorized data transfers

Generated by OpenCVE AI on August 2, 2026 at 02:23 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-q98v-9f9w-f49q	Temporal does not enforce authentication and authorization for the streaming AdminService/StreamWorkflowReplicationMessages endpoint

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact Low

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.606% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/temporalio/temporal/releases/tag/v1.28.4
https://github.com/temporalio/temporal/releases/tag/v1.29.6
https://github.com/temporalio/temporal/releases/tag/v1.30.4
https://github.com/temporalio/temporal/releases/tag/v1.31.2

History

Jul 8, 2026 7:45 PM Description updated. Added references View changes

Type	Values Removed	Values Added
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. Temporal Cloud is not affected.	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.
References		https://github.com/temporalio/temporal/releases/tag/v1.31.2

Apr 13, 2026 5:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Apr 13, 2026 1:00 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Temporal Temporal temporal
Vendors & Products		Temporal Temporal temporal

Apr 10, 2026 9:15 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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. Temporal Cloud is not affected.
Title		Missing Authentication on Streaming gRPC Replication Endpoint
Weaknesses		CWE-306
References		https://github.com/temporalio/temporal/releases/tag/v1.28.4 https://github.com/temporalio/temporal/releases/tag/v1.29.6 https://github.com/temporalio/temporal/releases/tag/v1.30.4
Metrics		cvssV4_0 `{'score': 6.3, '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/S:N/AU:N/R:U/RE:L'}`