Vulnerability · Published Mar 26, 2026 · Assigned by GitHub_M

CVE-2026-28788Open WebUI's process_files_batch() endpoint missing ownership check, allows unauthorized file overwrite

High 7.1

In plain English

A high-severity authorization bypass via user-controlled key in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 3.0% (higher than 87% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)3.0%top 12.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.8.6	GHSA-jjp7-g2jw-wh3j
PyPI	open-webui	0.8.6	PYSEC-2026-2742

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	< 0.8.6

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-jjp7-g2jw-wh3j x_refsource_CONFIRM