# 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.

- **Severity:** Critical 9.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N`)
- **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:** Yes
- **Published:** 2 Jun 2026
- **Updated:** 3 Jun 2026
- **Also known as:** BIT-authentik-2026-42849, GHSA-pgff-5mx8-fqj3

## 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 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-42849?

1 open source package ship an affected version, including authentik. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `authentik` | Bitnami | All versions | 2025.12.5, 2026.2.3 |

Products: 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.

## 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](https://insights.sbomify.com/CVE-2026-49448/): authentik: SourceStage bypass via empty POST (critical 9.8)
- [CVE-2023-46249](https://insights.sbomify.com/CVE-2023-46249/): authentik potential installation takeover when default admin user is deleted (critical 9.7)
- [CVE-2022-23555](https://insights.sbomify.com/CVE-2022-23555/): authentik vulnerable to Improper Authentication via invitation URL token reuse (critical 9.4)
- [CVE-2026-25227](https://insights.sbomify.com/CVE-2026-25227/): authentik affected by Remote Code Execution via Context Key Injection in PropertyMapping Test Endpoint (critical 9.1)
- [CVE-2024-47070](https://insights.sbomify.com/CVE-2024-47070/): authentik vulnerable to password authentication bypass via X-Forwarded-For HTTP header (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42849 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-42849 in the wild and no public exploit code.

Affected packages and fixed versions:
- authentik (Bitnami): affected all versions; fixed in 2025.12.5, 2026.2.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42849/ (Markdown: https://insights.sbomify.com/CVE-2026-42849/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42849
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42849
- OSV: https://osv.dev/vulnerability/CVE-2026-42849

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42849/
Summaries are generated and may contain mistakes; the official description above is the record.