Upstream information
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.SUSE information
Overall state of this security issue: Resolved
This issue is currently rated as having important severity.
| CVSS detail | CNA (GitHub) |
|---|---|
| Base Score | 8.5 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N |
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Changed |
| Confidentiality Impact | High |
| Integrity Impact | Low |
| Availability Impact | None |
| CVSSv3 Version | 3.1 |
List of released packages
| Product(s) | Fixed package version(s) | References |
|---|---|---|
| SUSE Linux Enterprise Server 16.1 |
| Patchnames: SUSE Linux Enterprise Server 16.1 GA govulncheck-vulndb-0.0.20260916T180043-160100.1.1 (aarch64,ppc64le,s390x,x86_64) |
| SUSE Linux Enterprise Server for SAP applications 16.1 |
| Patchnames: SUSE Linux Enterprise Server for SAP applications 16.1 GA govulncheck-vulndb-0.0.20260916T180043-160100.1.1 (aarch64,ppc64le,s390x,x86_64) |
SUSE Timeline for this CVE
CVE page created: Thu Jul 30 14:42:24 2026CVE page last modified: Wed Oct 28 15:25:57 2026