CVE-2026-54015: open-webui Improper Access Control

Vulnerability summary

CVE-2026-54015 is a medium (CVSS 6.4) Improper Access Control vulnerability in open-webui. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 17.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 23-06-2026
   PublishedVulnerability first disclosed.
2. 24-06-2026
   Last modifiedVulnerability information updated.

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, Open WebUI's prompt version-history endpoints authorize the prompt_id in the URL but then act on caller-supplied history IDs without verifying that the history row belongs to that prompt (history_entry.prompt_id == prompt.id). This affects /api/v1/prompts/id/{prompt_id}/history/diff, /api/v1/prompts/id/{prompt_id}/update/version, and /api/v1/prompts/id/{prompt_id}/history/{history_id}. An authenticated user with access to any prompt they control, plus a victim prompt_history.id, can read or delete another user's private prompt history. This vulnerability is fixed in 0.9.6.

• CWE-284Improper Access ControlThe product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
• CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.