CVE-2026-3514
Authentication Bypass in prefecthq/prefect
CVE-2026-3514 is a high vulnerability (CVSS 7.5) in Prefect, published June 2, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.48%, the 41st percentile. Fixed in prefect 3.6.22.dev7.
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.5
Authentication Bypass in prefecthq/prefect
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.
- Record
CVE-2026-3514- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
EUVDEUVD-2026-33884
7.5
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.
- Record
EUVD-2026-33884- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-c635-393c-hcx2
7.5
Prefect has an Authentication Middleware Bypass when URL paths are appended with 'health' or 'ready'
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.
- Record
GHSA-c635-393c-hcx2- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
NVD
7.5
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.
- Record
CVE-2026-3514- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
OSV
7.5
Authentication Bypass in prefecthq/prefect
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.
- Record
CVE-2026-3514- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
OSVGHSA-c635-393c-hcx2
7.5
Prefect has an Authentication Middleware Bypass when URL paths are appended with 'health' or 'ready'
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.
- Record
GHSA-c635-393c-hcx2- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
OSVPYSEC-2026-2261
7.5
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.
- Record
PYSEC-2026-2261- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVROOT-APP-PYPI-CVE-2026-3514 No score
CVE-2026-3514 in rootio-prefect - Patched by Root
Root has patched CVE-2026-3514 in the rootio-prefect package for Root:PyPI. Multiple fixed versions available.
- Record
ROOT-APP-PYPI-CVE-2026-3514- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
prefectPyPI |
before 3.6.22.dev7 | 3.6.22.dev7 |
prefectPyPI |
before 3.6.22.dev7, plus listed versions 0.10.00.10.10.10.20.10.30.10.4 Show 45 moreShow less0.10.50.10.60.10.70.11.00.11.10.11.20.11.30.11.40.11.50.12.00.12.10.12.20.12.30.12.40.12.50.12.60.13.00.13.10.13.100.13.110.13.120.13.130.13.140.13.150.13.160.13.170.13.180.13.190.13.20.13.30.13.40.13.50.13.60.13.70.13.80.13.90.14.00.14.10.14.100.14.110.14.120.14.130.14.140.14.150.14.16 |
3.6.22.dev7 |
prefectPyPI |
before 3.6.22, plus listed versions 0.10.00.10.10.10.20.10.30.10.4 Show 45 moreShow less0.10.50.10.60.10.70.11.00.11.10.11.20.11.30.11.40.11.50.12.00.12.10.12.20.12.30.12.40.12.50.12.60.13.00.13.10.13.100.13.110.13.120.13.130.13.140.13.150.13.160.13.170.13.180.13.190.13.20.13.30.13.40.13.50.13.60.13.70.13.80.13.90.14.00.14.10.14.100.14.110.14.120.14.130.14.140.14.150.14.16 |
3.6.22 |
rootio-prefectRoot:PyPI |
before 2.11.5+root.io.7 | 2.11.5+root.io.7 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-02 | created | CVE List, EUVD, GitHub Advisories, NVD, OSV |
References
huntr.com/bounties/c540e5e1-f74f-44f4-bfa0-9764ff6daa75
github.com/prefecthq/prefect/commit/e21617125335025b4b27e7d6f0ca028e8e8f3b79
nvd.nist.gov/vuln/detail/CVE-2026-3514
github.com/advisories/GHSA-c635-393c-hcx2
github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3514.json
github.com/PrefectHQ/prefect
Left out here: 1,379 versions. The JSON record has them.