authentik CVE-2026-72537

The attacker must possess a valid source-scoped SCIM provisioning token issued by the targeted authentik instance - unauthenticated exploitation is not possible. The authentik deployment must have at least one SCIM provisioning source configured and active, which is a non-default configuration requiring deliberate administrative setup; instances with no SCIM sources are not affected. The attacker must know or be able to enumerate the username of the target account, such as the widely-known default superuser username 'akadmin' or any other account whose username can be inferred or guessed. The limiting factors are: (1) possession of any SCIM source token regardless of its intended scope, (2) SCIM sources being enabled in the deployment, and (3) knowledge of a target username. No elevated privileges, user interaction, or special network position beyond API access is required once these conditions are met.

The provided CVSS 3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) accurately reflects the severity: network-accessible, low attack complexity, low privilege required, no user interaction, and full confidentiality, integrity, and availability impact. The PR:L metric maps to possession of a source-scoped SCIM token - a limited credential by design but sufficient for full superuser takeover due to the scope validation failure. EPSS data is absent from the source intelligence, so probabilistic exploitation likelihood cannot be quantified from this dataset. No CISA KEV listing is present, and no public exploit code is identified at time of analysis - these are distinct signals from severity. Despite the absence of confirmed exploitation, the real-world risk is materially elevated: the attack path is simple (craft a SCIM user payload targeting a known username), requires no complexity or user interaction, and the impact ceiling is full identity infrastructure compromise. Organizations that have issued SCIM provisioning tokens to third-party or loosely trusted systems should treat this as high priority. Risk is lower for deployments where SCIM provisioning is entirely disabled or where tokens are held exclusively by highly trusted internal services with no external exposure.

An attacker who has obtained a source-scoped SCIM provisioning token - for example, through a compromised third-party HR or directory synchronization system - sends a crafted SCIM POST or PUT request to the authentik SCIM endpoint, specifying the username of a known superuser account (such as the default 'akadmin'). The authentik SCIM ingest function matches the provisioned user to the existing local superuser by username and silently adopts that account, allowing the attacker to overwrite the superuser's credentials or attributes using only the limited SCIM credential. No public exploit code has been identified at time of analysis, but the attack mechanics follow directly from the described behavior and require no special tooling beyond standard SCIM API calls.