Security Vulnerabilities
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.0, a Stored Cross-Site Scripting (XSS) vulnerability exists in the Banner component due to an improper sanitization order (specifically, DOMPurify is executed before the marked library). This vulnerability allows a compromised or malicious administrator to plant a malicious payload in the global banner. Crucially, this vector enables Privilege Escalation, as the malicious banner is rendered for all users, including the Super Admin (Primary Admin). Consequently, the payload successfully bypasses the existing security mechanism. An attacker can leverage this to steal the Super Admin's session token This vulnerability is fixed in 0.8.0.
CVSS Score
8.1
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the channel webhook create/update flow accepts arbitrary profile_image_url values, including data:image/svg+xml;base64,... payloads. The profile image endpoint then decodes and serves this SVG as image/svg+xml without sanitization, allowing attacker-controlled script handlers (for example onload) to execute when the profile-image URL is opened in the browser. This vulnerability is fixed in 0.9.3.
CVSS Score
7.4
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the audio transcription upload endpoint takes the file extension from the user-supplied filename and saves the file under CACHE_DIR/audio/transcriptions/.. The /cache/{path} route serves these files via FileResponse, which sets Content-Type from the on-disk extension and emits no Content-Disposition. A verified user with the default-on chat.stt permission can upload a polyglot WAV+HTML file named pwn.html and trick any other user into opening the resulting URL — the response comes back as text/html and any embedded <script> runs in the Open WebUI origin. This vulnerability is fixed in 0.9.3.
CVSS Score
8.7
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the POST /api/v1/notes/{id}/pin endpoint performs a write operation (toggling the is_pinned field) but only checks for read permission. Users with read-only access to a shared note can pin/unpin it, which is a state-modifying action that should require write permission. This vulnerability is fixed in 0.9.3.
CVSS Score
3.5
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, an application-wide Cross-Site Request Forgery (CSRF) vulnerability was found Open-WebUl's image uploading functionality. An attacker can set an image URL to a malicious endpoint, allowing them to perform actions on behalf of a victim user. Any authenticated user can exploit this vulnerability, and any user who views the compromised image (e.g., a profile picture) will unknowingly send a GET request to the attacker-controlled URL. This can lead to cookie theft, denial of service (DoS), or other malicious actions. This vulnerability is fixed in 0.9.3.
CVSS Score
4.6
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, his advisory tracks a regression of the original Excel-preview XSS (CVE-2026-44549). The same root cause — XLSX.utils.sheet_to_html() output rendered via {@html excelHtml} without DOMPurify — was reintroduced sometime after v0.8.0 and is exploitable again This vulnerability is fixed in 0.9.3.
CVSS Score
5.4
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, a Server-Side Request Forgery (SSRF) vulnerability exists in _process_picture_url() in backend/open_webui/utils/oauth.py (line ~1338). The function fetches arbitrary URLs from OAuth picture claims without applying validate_url(), allowing an attacker to force the server to make HTTP requests to internal resources and exfiltrate the full response. This vulnerability is fixed in 0.9.0.
CVSS Score
7.7
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.5.7, a user can modify another user's model even if its visibility is set to Private. By changing the access permissions during editing, unauthorized access can be gained. This vulnerability is fixed in 0.5.7.
CVSS Score
6.5
EPSS Score
0.0
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.1.124, the API does not properly validate that the user has an authorized user role of user. By default, when Open WebUI is configured with new sign-ups enabled, the default user role is set to pending. In this configuration, an administrator is required to go into the Admin management panel following a new user registration and reconfigure the user to have a role of either user or admin before that user is able to access the web application. This vulnerability is fixed in 0.1.124.
CVSS Score
7.3
EPSS Score
0.001
Published
2026-05-15
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.6.19, there's an IDOR in the channels message management system that allows authenticated users to modify or delete any message within channels they have read access to. The vulnerability exists in the message update and delete endpoints, which implement channel-level authorization but completely lack message ownership validation. While the frontend correctly implements ownership checks (showing edit/delete buttons only for message owners or admins), the backend APIs bypass these protections by only validating channel access permissions without verifying that the requesting user owns the target message. This creates a client-side security control bypass where attackers can directly call the APIs to modify other users' messages. This vulnerability is fixed in 0.6.19.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-05-15