What is the CVSS score of CVE-2026-28786?

CVE-2026-28786 has a CVSS 3.1 base score of 4.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N. EPSS exploitation probability: 0.0%.

Which versions of Open Webui are affected by CVE-2026-28786?

Organizations using Open WebUI should be aware of moderate risk from CVE-2026-28786, a path traversal vulnerability rated CVSS 4.3. This could allow unauthorized file access.. A patch is available.

How to fix or mitigate CVE-2026-28786?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Review file handling controls.

Open Webui CVE-2026-28786

EUVD-2026-16480 MEDIUM

Path Traversal (CWE-22)

2026-03-27 security-advisories@github.com

Information Disclosure Path Traversal Open Webui Openwebui

4.3

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

4.3 MEDIUM

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

EUVD ID Assigned

Mar 27, 2026 - 00:22 euvd

EUVD-2026-16480

Analysis Generated

Mar 27, 2026 - 00:22 vuln.today

CVE Published

Mar 27, 2026 - 00:16 nvd

MEDIUM 4.3

DescriptionGitHub Advisory

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.6, an unsanitized filename field in the speech-to-text transcription endpoint allows any authenticated non-admin user to trigger a FileNotFoundError whose message - including the server's absolute DATA_DIR path - is returned verbatim in the HTTP 400 response body, confirming information disclosure on all default deployments. Version 0.8.6 patches the issue.

AnalysisAI

Open WebUI versions prior to 0.8.6 disclose the server's absolute DATA_DIR path to any authenticated non-admin user via unsanitized filename handling in the speech-to-text transcription endpoint, which returns FileNotFoundError messages in HTTP 400 responses. This information disclosure affects all default deployments and requires only user-level authentication to trigger. The vulnerability has been patched in version 0.8.6, and no public exploit code or active exploitation has been identified at time of analysis.

Technical ContextAI

Open WebUI is a self-hosted AI platform designed for offline operation. The vulnerability exists in the speech-to-text (STT) transcription endpoint, which accepts a filename parameter without proper sanitization. The root cause is classified under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory, also known as Path Traversal), though the vulnerability manifests as information disclosure rather than file access. When a non-existent or specially crafted filename is submitted by an authenticated user, the application fails to sanitize error messages before returning them in HTTP response bodies. The FileNotFoundError exception handling exposes the full server filesystem path (DATA_DIR) in the 400-level HTTP response, allowing attackers to enumerate the server's directory structure and confirm deployment configurations. The vulnerability affects the REST API endpoint handling audio file transcription requests and requires valid user credentials (PR:L in CVSS vector), limiting attack surface to authenticated users without administrative privileges.

RemediationAI

Upgrade Open WebUI to version 0.8.6 or later, which patches the unsanitized filename field in the speech-to-text endpoint. Until patching is completed, operators should restrict access to the STT transcription endpoint via firewall rules or reverse proxy configurations, limiting it to trusted network ranges or specific administrative users. Additionally, monitor HTTP 400 responses from the transcription endpoint for suspicious filename parameters that may indicate reconnaissance attempts. The vendor advisory at https://github.com/open-webui/open-webui/security/advisories/GHSA-vvxm-vxmr-624h provides the patch release and should be reviewed for deployment guidance.