CVE-2026-33374 Unbounded memory allocation in the Prometheus rule conversion API
Authenticated users can crash Grafana servers by sending large payloads to the Prometheus rule conversion API due to missing size limits.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33374?
CVE-2026-33374 is a medium-severity denial of service vulnerability in Grafana Enterprise, published on 13 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The Prometheus rule conversion API endpoints in Grafana do not limit request body size, allowing authenticated users to trigger unbounded memory allocations that can crash the server through out-of-memory conditions.
Which versions are affected by CVE-2026-33374?
1 open source package ship an affected version, including grafana.
| Package | Affected | Fixed in |
|---|---|---|
grafana Bitnami | From 12.0.0 | 12.4.13, 13.0.11, 13.1.8, 13.2.4 |
How do I fix CVE-2026-33374?
Upgrade grafana to a fixed version for your release line: 12.4.13, 13.0.11, 13.1.8 or 13.2.4.
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-2026-33374 being exploited?
There is no known exploitation of CVE-2026-33374 in the wild and no public exploit code.
Sources
Also known as BIT-grafana-2026-33374, GHSA-5mj5-pfmr-wxjp, UBUNTU-CVE-2026-33374.