authentik: Denial of Service via Document Type Declarations in SAML Messages
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-770.
Summary
authentik is an open-source identity provider. Prior to 2026.2.7, 2026.5.7, and 2026.8.2, an unauthenticated attacker can submit a malformed SAML message to an authentik deployment using SAML in either the identity-provider or SAML source role. The message can stop the worker handling /application/saml/* or /source/saml/*, causing the requests assigned to that worker to fail. Worker process termination and automatic restart do not destroy database-backed sessions, but continued malicious messages can cause a sustained share of legitimate traffic to fail. Other protocol implementations are not affected. This issue is fixed in versions 2026.2.7, 2026.5.7, and 2026.8.2.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| goauthentik | authentik | before 2026.2.7; 2026.5.0 to before 2026.5.7; 2026.8.0 to before 2026.8.2 | 2026.2.7, 2026.5.7, 2026.8.2 | Patch available | CNA |
- authentik Vendorgoauthentik Affected before 2026.2.7; 2026.5.0 to before 2026.5.7; 2026.8.0 to before 2026.8.2 Fixed in 2026.2.7, 2026.5.7, 2026.8.2 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:goauthentik:authentik:*:*:*:*:*:*:*:* | — | — | goauthentik |
- cpe:2.3:a:goauthentik:authentik:*:*:*:*:*:*:*:* Versions — — ·goauthentik
Remediation
- Fix · CNA authentik (goauthentik) Fixed in 2026.2.7, 2026.5.7, 2026.8.2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-94613
- 2026-10-21 EPSS moved to the 50th–90th percentile
References
Other 15
- https://github.com/goauthentik/authentik/security/advisories/GHSA-cxwx-9x59-28qm
- https://github.com/goauthentik/authentik/pull/25959
- https://github.com/goauthentik/authentik/pull/25964
- https://github.com/goauthentik/authentik/pull/25969
- https://github.com/goauthentik/authentik/pull/25974
- https://github.com/goauthentik/authentik/commit/03d19d63b8d8dd7bc3de7cf6e57c6df341a9fc86
- https://github.com/goauthentik/authentik/commit/4cf2f803b1c2ef38c224eead375fd057a10ee8ac
- https://github.com/goauthentik/authentik/commit/732adad26bb97361b6bf25ef138df5c16471ba1f
- https://github.com/goauthentik/authentik/commit/a029f5372295bfeb1e334855f78601681cdc9a2d
- https://docs.goauthentik.io/releases/2026.2#fixed-in-202627
- https://docs.goauthentik.io/releases/2026.5#fixed-in-202657
- https://docs.goauthentik.io/releases/2026.8#fixed-in-202682
- https://github.com/goauthentik/authentik/releases/tag/version/2026.2.7
- https://github.com/goauthentik/authentik/releases/tag/version/2026.5.7
- https://github.com/goauthentik/authentik/releases/tag/version/2026.8.2
More goauthentik vulnerabilities
- TI-2026-36603 authentik: SourceStage bypass via empty POST CVSS 3.1CRITICAL 9.8
- TI-2022-07608 authentik vulnerable to Improper Authentication via invitation URL token reuse CVSS 3.1CRITICAL 9.4
- TI-2026-36598 authentik: `UserSourceConnection.user` and `GroupSourceConnection.group` are changeable through the API CVSS 3.1HIGH 8.8
- TI-2022-22816 authentik allows existing authenticated users to create arbitrary accounts CVSS 3.1MEDIUM 6.4
- TI-2026-41431 authentik: Account Takeover via SAML NameID Comment Truncation CVSS 4.0CRITICAL 9.4
- TI-2024-25628 Insufficient access control for OAuth2 Device Code flow in authentik CVSS 3.1CRITICAL 9.8
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences