Open Redirect in OAuth2 Proxy
Priority LOW 26CWE-601Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-601.
Summary
In OAuth2 Proxy from version 5.1.1 and less than version 6.0.0, users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access. This redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites. This has been fixed in version 6.0.0.
Why it matters now
EPSS 0.00896 59th percentileScored 2026-11-07
Fix Fixed OAuth2 Proxy (OAuth2 Proxy): 6.0.0github.com/oauth2-proxy/oauth2-proxy (Go): 6.0.0
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| oauth2-proxy | OAuth2 Proxy | 5.1.1 to before 6.0.0 | 6.0.0 | Patch available | CNA |
| — | github.com/oauth2-proxy/oauth2-proxy (Go) | 5.1.1 to before 6.0.0 | 6.0.0 | Patch available | GHSA-5m6c-jp6f-2vcv |
- OAuth2 Proxy Vendoroauth2-proxy Affected 5.1.1 to before 6.0.0 Fixed in 6.0.0 Patch available CNA
- github.com/oauth2-proxy/oauth2-proxy (Go) Vendor— Affected 5.1.1 to before 6.0.0 Fixed in 6.0.0 Patch available GHSA-5m6c-jp6f-2vcv
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:oauth2_proxy_project:oauth2_proxy:*:*:*:*:*:*:*:* | 5.1.1 to before 6.0.0 | Vulnerable | oauth2-proxy |
- cpe:2.3:a:oauth2_proxy_project:oauth2_proxy:*:*:*:*:*:*:*:* Versions 5.1.1 to before 6.0.0 Vulnerable ·oauth2-proxy
Remediation
- Fix · CNA OAuth2 Proxy (OAuth2 Proxy) Fixed in 6.0.0
- Fix · GHSA-5m6c-jp6f-2vcv github.com/oauth2-proxy/oauth2-proxy (Go) Fixed in 6.0.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2020-4037
- 2026-10-03 Alias added: GHSA-5m6c-jp6f-2vcv
References
Advisory 2
More oauth2-proxy Oauth2 Proxy vulnerabilities
- TI-2025-34353 OAuth2-Proxy has authentication bypass in oauth2-proxy skip_auth_routes due to Query Parameter inclusion CVSS 3.1CRITICAL 9.1
- TI-2026-29315 OAuth2 Proxy has an Authentication Bypass via X-Forwarded-Uri Header Spoofing CVSS 3.1CRITICAL 9.1
- TI-2026-26722 OAuth2 Proxy: Health Check User-Agent Matching Bypasses Authentication in auth_request Mode CVSS 3.1CRITICAL 9.1
- TI-2026-29698 OAuth2 Proxy has an Authentication Bypass via Fragment Confusion in skip_auth_routes and skip_auth_regex CVSS 3.1HIGH 8.2
- TI-2017-14408 CSRF in Bitly oauth2_proxy 2.1 during authentication flow CVSS 3.0HIGH 8.8
- TI-2020-08927 Open Redirect in OAuth2 Proxy CVSS 3.1HIGH 7.1
Sources
- CVE-2020-4037 · CVE Program
- CVE-2020-4037 · NVD
- FIRST EPSS
- GHSA-5m6c-jp6f-2vcv · GitHub Advisory Database · CC BY 4.0
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