# CVE-2026-40574

> Vulnerability · severity: **MEDIUM** (CVSS 6.8).

## Description

OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Prior to 7.15.2, an authorization bypass exists in OAuth2 Proxy as part of the email_domain enforcement option. An attacker may be able to authenticate with an email claim such as attacker@evil.com@company.com and satisfy an allowed domain check for company.com, even though the claim is not a valid email address. The issue ONLY affects deployments that rely on email_domain restrictions and accept email claim values from identity providers or claim mappings that do not strictly enforce normal email syntax. This vulnerability is fixed in 7.15.2.

## Key facts

- **CVE ID:** CVE-2026-40574
- **Published:** 2026-04-21
- **CVSS severity:** MEDIUM
- **CVSS base score:** 6.8
- **CWE codes:** CWE-863

## Affected products

- `oauth2_proxy_project:oauth2_proxy`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40574

## Citation

> AI Analytics. CVE-2026-40574. Retrieved 2026-07-17 from https://api.ai-analytics.org/cve/CVE-2026-40574. Derived from NIST NVD. Licensed CC0.

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