CVE-2026-54009 json
Open WebUI: Cross-user file disclosure via /api/chat/completions image_url field
published 2026-06-17 4 mo ago modified 2026-07-20 3 mo ago also GHSA-wch8-mhj5-9frg , PYSEC-2026-2766 , EUVD-2026-38533
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 32%
- public exploits
- 0
- none known
Summary
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, POST /api/chat/completions accepts an image_url.url value that, when it does NOT start with http://, https://, or data:image/, is interpreted as a file id and resolved against the global file table with no ownership check. an authenticated user can therefore set image_url.url to another user's file id, the server reads that file from disk, base64-encodes it, and injects the data URI into the LLM request. the user then prompts the LLM to describe / OCR the file and reads the content back. This vulnerability is fixed in 0.9.6.
Patch / fix
- pypi open-webui 0.9.6
- openwebui open_webui 0.9.6
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/open-webui/open-webui/security/advisories/GHSA-wch8-mhj5-9frg referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| GitHub | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| OSV | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | open-webui | <0.9.6 |
0.9.6 |
Affected products
- open-webui open-webui
Classification
- Weakness
-
- CWE-639 Authorization Bypass Through User-Controlled Key
References
-
github.com
/open-webui/open-webui/security/advisories/GHSA-wch8-mhj5-9frg
exploit, web, vendor-advisory, mitigation
-
nvd.nist.gov
/vuln/detail/CVE-2026-54009
advisory
-
github.com
/advisories/GHSA-wch8-mhj5-9frg
advisory
-
github.com
/open-webui/open-webui
package
-
github.com
/pypa/advisory-database/tree/main/vulns/open-webui/PYSEC-2026-2766.yaml
web
-
pypi.org
/project/open-webui
web, package
Sources
- CVE List CVE-2026-54009
- GitHub Advisory GHSA-wch8-mhj5-9frg
- NVD CVE-2026-54009
- OSV PYSEC-2026-2766
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.