Auth bypass in Prefect
CVE-2026-3514
In version 3.6.19 of prefecthq/prefect, an authentication bypass vulnerability exists due to the improper handling of URL path exemptions for health check probes. Specifically, the authentication middleware exempts any URL path ending with 'health' or 'ready' from authentication checks. This allows an attacker to create resources with names ending in 'health' or 'ready' and access them without authentication. Affected endpoints include those for variables, flows, work pools, work queues, and deployments. This vulnerability can lead to unauthorized access to sensitive information, such as API keys and database credentials, stored in Prefect Variables.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.006 (48.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.002
Affected products
- Prefect
- Prefecthq Prefecthq/prefect — versions unspecified
Weakness classification (CWE)
References
- huntr.com/bounties/c540e5e1-f74f-44f4-bfa0-9764ff6daa75 (Exploit, Third Party Advisory)
- github.com/prefecthq/prefect/commit/e21617125335025b4b27e7d6f0ca028e8e8f3b79 (Patch)
Frequently asked questions
- What is CVE-2026-3514?
- CVE-2026-3514 is a high-severity vulnerability in Prefect, classified under Incorrect Authorization. CVSS score: 7.5/10. Published 2026-06-02.
- How severe is CVE-2026-3514?
- High severity. CVSS v3 base score is 7.5 out of 10.