CVE-2026-3514: Authentication Bypass in prefecthq/prefect

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-02 · updated 2026-07-22
Weakness: CWE-863

Description

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.

Affected products

prefecthq/prefect: before 3.6.22 — fixed in 3.6.22

How to fix

Upgrade to a fixed version: prefecthq/prefect 3.6.22. Check the vendor advisory for mitigations.

References

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