What is CVE-2026-21723?

CVE-2026-21723 is a security advisory published by Grafana Labs Security. DoS Vulnerability in Templates Test endpoint

Why does CVE-2026-21723 have no CVE ID yet?

Grafana Labs Security published this advisory directly to customers before NVD assigned a CVE ID. This is the embargo-window disclosure pattern — vendors notify customers on day 0; NVD's public record follows days to weeks later.

Which products are affected by CVE-2026-21723?

CVE-2026-21723 affects 1 product, including: grafana.

CVE-2026-21723Disclosed before NVD

DoS Vulnerability in Templates Test endpoint

Vendor

Grafana Labs Security

Published

July 22, 2026

Last Modified

—

📋 Description

The alertmanager templates test endpoint (/api/alertmanager/grafana/config/api/v1/templates/test) can execute templates with no memory limits. Mass-executing templates in a short period causes OOM and crashes the Grafana service. The endpoint requires very low privileges and is exploitable with anonymous access enabled. Thanks to the researcher nacl for this report!

🎯 Affected products1

grafana

🔗 References (1)

advisoryhttps://grafana.com/security/security-advisories/cve-2026-21723/