CVE-2025-64484
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-11-10

Last updated on: 2025-11-12

Assigner: GitHub, Inc.

Description
OAuth2-Proxy is an open-source tool that can act as either a standalone reverse proxy or a middleware component integrated into existing reverse proxy or load balancer setups. In versions prior to 7.13.0, all deployments of OAuth2 Proxy in front of applications that normalize underscores to dashes in HTTP headers (e.g., WSGI-based frameworks such as Django, Flask, FastAPI, and PHP applications). Authenticated users can inject underscore variants of X-Forwarded-* headers that bypass the proxy’s filtering logic, potentially escalating privileges in the upstream app. OAuth2 Proxy authentication/authorization itself is not compromised. The problem has been patched with v7.13.0. By default all specified headers will now be normalized, meaning that both capitalization and the use of underscores (_) versus dashes (-) will be ignored when matching headers to be stripped. For example, both `X-Forwarded-For` and `X_Forwarded-for` will now be treated as equivalent and stripped away. For those who have a rational that requires keeping a similar looking header and not stripping it, the maintainers introduced a new configuration field for Headers managed through the AlphaConfig called `InsecureSkipHeaderNormalization`. As a workaround, ensure filtering and processing logic in upstream services don't treat underscores and hyphens in Headers the same way.
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Meta Information
Published
2025-11-10
Last Modified
2025-11-12
Generated
2026-05-07
AI Q&A
2025-11-11
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
oauth2-proxy oauth2-proxy *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-644 The product does not neutralize or incorrectly neutralizes web scripting syntax in HTTP headers that can be used by web browser components that can process raw headers, such as Flash.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability affects OAuth2-Proxy versions prior to 7.13.0 when deployed in front of applications that normalize underscores to dashes in HTTP headers. Authenticated users can inject underscore variants of X-Forwarded-* headers that bypass the proxy's filtering logic, potentially allowing privilege escalation in the upstream application. The OAuth2 Proxy's own authentication and authorization are not compromised. The issue was fixed in version 7.13.0 by normalizing headers to treat underscores and dashes equivalently when filtering.


How can this vulnerability impact me? :

This vulnerability can allow authenticated users to bypass header filtering in OAuth2-Proxy and escalate their privileges in the upstream application. This could lead to unauthorized access or actions within the protected application, potentially compromising sensitive data or functionality.


What immediate steps should I take to mitigate this vulnerability?

Upgrade OAuth2 Proxy to version 7.13.0 or later, where the vulnerability is patched by normalizing headers to treat underscores and dashes equivalently. As a workaround, ensure that filtering and processing logic in upstream services do not treat underscores and hyphens in HTTP headers the same way to prevent bypassing the proxy's filtering logic.


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