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CVE-2026-5724 — server

CVE-2026-5724 is a Missing Authentication vulnerability in go.temporal.io/server. A fix is available for go.temporal.io/server — see the affected versions and patch details below.

Missing Authentication on Streaming gRPC Replication Endpoint

Also known asGHSA-q98v-9f9w-f49qGO-2026-5578
Published
Updated
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-5724.

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk
0.00%0.39%0.78%1.17%0.0%0.5%May 26Sep 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected
🐹go.temporal.io/server🐹go.temporal.io/server🐹go.temporal.io/server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

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 Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogo.temporal.io/serverall versions1.28.4go get go.temporal.io/server@v1.28.4
🐹Gogo.temporal.io/server≥ 1.29.0-135.0&&< 1.29.61.29.6go get go.temporal.io/server@v1.29.6
🐹Gogo.temporal.io/server≥ 1.30.0-143.0&&< 1.30.41.30.4go get go.temporal.io/server@v1.30.4

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.temporal.io/server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update go.temporal.io/server to 1.28.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-5724 is resolved across your whole dependency graph.

  3. Workarounds

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

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 replicatio
O3 Security · Impact-Aware SCA

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CVE-2026-5724: server — Fixed in 1.28.4