Kanidm: Stored HTML injection in "passkey-enrolment" partial via displayname → htmx-driven authenticated request forgery
Date: 2026-05
Affected: rust/kanidm
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-79
CVSS: 6.1 (CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N)

### Summary The kanidmd web UI renders the WebAuthn passkey-registration challenge as raw JSON inside an inline `<script id="data">` element using the Askama `|safe` filter. The challenge embeds the account's `displayname`, which `serde_json` serialises without escaping `<`/`>`. A `displayname` containing `</script>` therefore terminates the script element early and injects arbitrary HTML into the credential-update page. Because the page is htmx-driven and the server's CSP allows `'unsafe-eval'`, injected `hx-*` attributes can issue authenticated same-origin API requests with the viewer's bearer cookie. ### Impact An authenticated attacker who is a member of `idm_people_admins` can write the `displayname` of any `Person` entry — including high-privilege persons — because `idm_acp_people_pii_manage` carries no high-privilege exclusion filter. When the targeted high-privilege user later opens **Add Passkey** on their own credential-update page (`/ui/reset`), the injected markup is swapped into the DOM and htmx fires attacker-chosen same-origin requests authenticated as the victim. This allows a helpdesk-tier operator to escalate to `idm_admins` (e.g. by POSTing themselves into the group) or otherwise act with the victim's session. The self-write path (`idm_people_self_name_write`) is self-XSS only and is not counted toward impact. Even without the htmx vector, the breakout permits `<meta http-equiv='refresh'>` open-redirect and arbitrary defacement of the credential page. #


Mitigations:

Architectural layers (MAESTRO):