What is CVE-2026-42849?

CVE-2026-42849 is a critical-severity vulnerability in Goauthentik Authentik, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-06-02.

How severe is CVE-2026-42849?

Critical severity. CVSS v3 base score is 9.3 out of 10.

XSS in Goauthentik Authentik

CVE-2026-42849

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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.004 (28.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.

Affected products

Goauthentik Authentik — versions < 2025.12.5, < 2026.2.3

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42849?: CVE-2026-42849 is a critical-severity vulnerability in Goauthentik Authentik, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-06-02.
How severe is CVE-2026-42849?: Critical severity. CVSS v3 base score is 9.3 out of 10.