Improper Neutralization of HTTP Headers for Scripting Syntax Affecting oauth2-proxy-advanced-compat package, versions <7.13.0-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.66% (51st percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-OAUTH2PROXYADVANCEDCOMPAT-13961799
  • published14 Nov 2025
  • disclosed10 Nov 2025

Introduced: 10 Nov 2025

CVE-2025-64484  (opens in a new tab)
CWE-644  (opens in a new tab)

How to fix?

Upgrade Minimos:latest oauth2-proxy-advanced-compat to version 7.13.0-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream oauth2-proxy-advanced-compat package and not the oauth2-proxy-advanced-compat package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1