CVE-2026-5724

MEDIUM

Missing Authentication on Streaming gRPC Replication Endpoint

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-5724. PoCs published by tibrn.

AI-analyzed exploit summary The repository contains a functional exploit PoC for CVE-2026-5724, demonstrating an authentication bypass in Temporal's frontend gRPC service. The exploit leverages a missing authorization interceptor in the streaming gRPC chain to access privileged admin endpoints without credentials.

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.

Exploits (1)

github WORKING POC
by tibrn · poc
https://github.com/tibrn/CVE-2026-5724

The repository contains a functional exploit PoC for CVE-2026-5724, demonstrating an authentication bypass in Temporal's frontend gRPC service. The exploit leverages a missing authorization interceptor in the streaming gRPC chain to access privileged admin endpoints without credentials.

Classification
Working Poc 100%
Attack Type
Auth Bypass
Complexity
Trivial
Reliability
Reliable
Target: Temporal frontend service (gRPC API)
No auth needed
Prerequisites: Access to the Temporal frontend gRPC API
devstral-2 · analyzed May 03, 2026 Full analysis →

Scores

CVSS v4 6.3
EPSS 0.0051
EPSS Percentile 39.2%
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

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-306
Status published
Products (4)
go.temporal.io/server 0 - 1.28.4Go
Temporal Technologies, Inc./temporal 1.24.0 - 1.28.3
Temporal Technologies, Inc./temporal 1.24.0 - 1.29.5
Temporal Technologies, Inc./temporal 1.24.0 - 1.30.3
Published Apr 10, 2026
Tracked Since Apr 11, 2026