CVE-2025-64484

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure.

Exploit odds

0.7% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-11-10 22:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 09:54 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.7% in the next 30 days (EPSS).
• Severity: 8.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-11-10 22:15 UTC

Last modified

2026-06-17 09:54 UTC

Exploit probability

0.7% · EPSS, next 30 days

Weakness

CWE-644

Record status

Deferred

Attack profile CVSS 3.1 · 8.5

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-64484.md and follow it. Check whether this project is affected by CVE-2025-64484. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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