CVE-2026-40574
published 2026-04-21CVE-2026-40574: 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…
PriorityP341medium6.8CVSS 3.1
AVNACHPRLUINSUCHIHAN
EPSS
0.21%
11.0th percentile
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 [email protected]@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.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | oauth2-proxy_oauth2-proxy_v7 | >= 0 < 7.15.2 | 7.15.2 |
| oauth2-proxy | oauth2-proxy | < 7.15.2 | 7.15.2 |
| oauth2_proxy_project | oauth2_proxy | < 7.15.2 | 7.15.2 |
| rhceph | oauth2-proxy-rhel9 | — | — |
CVSS provenance
nvdv3.16.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
vendor_redhat6.8MEDIUM
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VulDB
oauth2-proxy OAuth2 Proxy up to 7.15.1 authorization (GHSA-c5c4-8r6x-56w3)
vuldb·2026-04-21·CVSS 6.8
CVE-2026-40574 [MEDIUM] oauth2-proxy OAuth2 Proxy up to 7.15.1 authorization (GHSA-c5c4-8r6x-56w3)
A vulnerability identified as problematic has been detected in oauth2-proxy OAuth2 Proxy up to 7.15.1. This impacts an unknown function. Performing a manipulation results in incorrect authorization.
This vulnerability is identified as CVE-2026-40574. The attack can be initiated remotely. There is not any exploit available.
You should upgrade the affected component.
GHSA
OAuth2 Proxy has an Authorization Bypass in Email Domain Validation via Malformed Multi-@ Email Claims
ghsa·2026-04-15
CVE-2026-40574 [MEDIUM] CWE-863 OAuth2 Proxy has an Authorization Bypass in Email Domain Validation via Malformed Multi-@ Email Claims
OAuth2 Proxy has an Authorization Bypass in Email Domain Validation via Malformed Multi-@ Email Claims
### Impact
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 `[email protected]@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. The practical risk ONLY exists in self-hosted or custom OIDC environments and federated setups where unexpected claim values can reach oauth2-proxy. Standard hosted providers th
Red Hat
github.com/oauth2-proxy/oauth2-proxy: OAuth2 Proxy: Authorization Bypass via malicious email claim
vendor_redhat·2026-04-21·CVSS 6.8
CVE-2026-40574 [MEDIUM] CWE-551 github.com/oauth2-proxy/oauth2-proxy: OAuth2 Proxy: Authorization Bypass via malicious email claim
github.com/oauth2-proxy/oauth2-proxy: OAuth2 Proxy: Authorization Bypass via malicious email claim
A flaw was found in OAuth2 Proxy, a reverse proxy providing authentication using OAuth2 providers. A remote attacker can exploit an authorization bypass vulnerability by crafting a malicious email claim. This allows the attacker to bypass `email_domain` restrictions, which are used to limit access to specific email domains, and gain unauthorized access. This issue specifically impacts deployments that rely on `email_domain` restrictions and accept email claims without strict email syntax enforcement.
Statement: A Moderate impact authorization bypass flaw exists in OAuth2 Proxy affecting deployments configured with `email_domain` restrictions. This vulnerability allows a remote attacker to b
No detection rules found.
No public exploits indexed.
2026-04-21
Published