high8.5
CVE-2026-47201
authentik's XML Signature Wrapping in SAML Source ACS allows authentication as arbitrary federated user
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | goauthentik.io | < 0.0.0-20260528144335-a370d76d23c7 | 0.0.0-20260528144335-a370d76d23c7 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Goauthentik | Authentik | before 2025.12.6 from 2026.2.0 before 2026.2.4 from 2026.5.0 before 2026.5.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-c3m2-jqmq-pvp3
- https://github.com/goauthentik/authentik/security/advisories/GHSA-c3m2-jqmq-pvp3
- https://github.com/goauthentik/authentik/commit/a370d76d23c7de0fceed064ca322e33e6ebf0119
- https://nvd.nist.gov/vuln/detail/CVE-2026-47201