CVE-2026-42849 authentik: Reflected XSS in SFE AutosubmitStage allows IDP account takeover
Reflected XSS in authentik's SFE AutosubmitStage allows attackers to hijack identity provider accounts.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-42849?
CVE-2026-42849 is a critical cross-site scripting vulnerability in goauthentik authentik, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, due to the implementation of stages in the SFE (Simple Flow Executor) in order to make the interface more compatible with legacy browsers, it was possible to use an XSS exploit in the AutosubmitStage. This issue has been patched in versions 2025.12.5 and 2026.2.3.
Weakness: CWE-79
Which versions are affected by CVE-2026-42849?
1 open source package ship an affected version, including authentik. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
authentik Bitnami | All versions | 2025.12.5, 2026.2.3 |
Products include Goauthentik Authentik.
How do I fix CVE-2026-42849?
Upgrade authentik to a fixed version for your release line: 2025.12.5 or 2026.2.3.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-42849 being exploited?
There is no known exploitation of CVE-2026-42849 in the wild and no public exploit code.
Other vulnerabilities in goauthentik authentik
- CVE-2026-49448 authentik: SourceStage bypass via empty POST
- CVE-2023-46249 authentik potential installation takeover when default admin user is deleted
- CVE-2022-23555 authentik vulnerable to Improper Authentication via invitation URL token reuse
- CVE-2026-25227 authentik affected by Remote Code Execution via Context Key Injection in PropertyMapping Test Endpoint
- CVE-2024-47070 authentik vulnerable to password authentication bypass via X-Forwarded-For HTTP header
Sources
Also known as BIT-authentik-2026-42849, GHSA-pgff-5mx8-fqj3.