CVE-2026-16652
CVE-2026-16652 is a high-severity vulnerability with a CVSS 4.0 base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-606.
Key facts
- Severity: High (CVSS 4.0 base score 7.1)
- EPSS exploit prediction: 0% (17th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-606
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-16652?
- 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.
- How severe is CVE-2026-16652?
- CVE-2026-16652 has a CVSS 4.0 base score of 7.1, rated high severity.
- Is CVE-2026-16652 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-16652?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-16652 published?
- CVE-2026-16652 was published on 2026-09-21 and last updated on 2026-09-22.
References
- https://github.com/temporalio/temporal/commit/c10c730e53ae394fffaefe44ba3722150fe40720
- https://github.com/temporalio/temporal/pull/11014
- https://github.com/temporalio/temporal/releases/tag/v1.30.7
- https://github.com/temporalio/temporal/releases/tag/v1.31.3
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