CVE-2026-47201
authentik: XML Signature Wrapping in SAML Source ACS allows authentication as arbitrary federated user
8.5
HIGH
CVSS 3.1
EPSS 0.06%
Description
authentik is an open-source identity provider. Prior to versions 2025.12.5, 2026.2.3, and 2026.5.1, authentik's SAML Source ACS endpoint is vulnerable to XML Signature Wrapping when validating upstream SAML responses. An attacker with any account at the upstream IdP can reuse a valid signed assertion to authenticate as another federated user. This issue has been patched in versions 2025.12.5, 2026.2.3, and 2026.5.1.
How to fix CVE-2026-47201
To remediate CVE-2026-47201, upgrade the affected package to a fixed version below.
- —upgrade to 2026.5.1 or later
- —upgrade to 0.0.0-20260528144335-a370d76d23c7 or later
Is CVE-2026-47201 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 2026.5.1
- from 0, < 0.0.0-20260528144335-a370d76d23c7
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.5 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |