CVE-2026-28788: Open WebUI's process_files_batch() endpoint missing ownership check, allows unauthorized file overwrite
Affected: open-webui · Exploitation: possible (1 to 10%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 87% of scored CVEs
DescriptionCVE.org
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.6, any authenticated user can overwrite any file's content by ID through the `POST /api/v1/retrieval/process/files/batch` endpoint. The endpoint performs no ownership check, so a regular user with read access to a shared knowledge base can obtain file UUIDs via `GET /api/v1/knowledge/{id}/files` and then overwrite those files, escalating from read to write. The overwritten content is served to the LLM via RAG, meaning the attacker controls what the model tells other users. Version 0.8.6 patches the issue.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- open-webui · open-webui< 0.8.6
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Possible (1 to 10%). EPSS between 1% and 10%.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Weakness
- Insecure Direct Object Reference
- Vendor
- open-webui
- Published
- March 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-28788 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.