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)

Published 2026-06-02 · last modified 2026-07-22.

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.

EPSS exploit prediction

EPSS: 0.005 (39.6th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 39.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Affected products

Goauthentik Authentik — versions < 2025.12.5, < 2026.2.3

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/goauthentik/authentik/security/advisories/GHSA-pgff-5mx8-fqj3 (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.