CVE-2026-16652 Temporal Server Schedule exclusion search can cause excessive CPU consumption
Authenticated users can cause excessive CPU consumption and service denial by creating schedules with exclusion calendars that reject all candidate times.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-16652?
CVE-2026-16652 is a high-severity denial of service vulnerability in Temporal Server, published on 21 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Temporal Server did not bound the work performed while searching for a Schedule's next action time. An authenticated caller with namespace write permission could create or update a Schedule that combines a fine-grained cadence with an exclusion calendar that rejects every candidate time, causing the server to evaluate excluded candidates without a per-search work budget. This can consume excessive CPU in Frontend and Schedule worker components. A persisted specification can also cause its backing Schedule Workflow to repeatedly fail and retry, allowing CPU consumption to continue without additional requests until the Schedule is deleted or its backing Workflow is terminated. Repeated or parallel exploitation can deny service. The issue affects availability only; it does not expose or modify Workflow data.
Weakness: CWE-606
Which versions are affected by CVE-2026-16652?
How do I fix CVE-2026-16652?
No fix has been published for CVE-2026-16652 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-16652 being exploited?
There is no known exploitation of CVE-2026-16652 in the wild and no public exploit code.
Sources
Also known as GHSA-pv35-7w89-v65c.