CVE-2026-16652
Temporal Server Schedule exclusion search can cause excessive CPU consumption
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.
INFO
Published Date :
Sept. 21, 2026, 12:17 p.m.
Last Modified :
Sept. 21, 2026, 12:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-16652
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 61241ed8-fa44-4f23-92db-b8c443751968 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Apply the latest Temporal Server patch release.
- Monitor server CPU usage after patching.
- Review and validate schedule configurations.
- Delete problematic schedules if needed.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-16652.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-16652 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-16652
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-16652 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-16652 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 21, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-606 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/16xxx/CVE-2026-16652.json">CVE-2026-16652</a> Added Reference https://github.com/temporalio/temporal/commit/c10c730e53ae394fffaefe44ba3722150fe40720 Added Reference https://github.com/temporalio/temporal/pull/11014 Added Reference https://github.com/temporalio/temporal/releases/tag/v1.30.7 Added Reference https://github.com/temporalio/temporal/releases/tag/v1.31.3