CVE-2026-45339 json
Open WebUI: API key endpoint restrictions bypassed via `x-api-key` header — full message processing on restricted endpoints
published 2026-05-14 5 mo ago modified 2026-11-03 5 d ago also GHSA-57q6-fvp4-pqmm , PYSEC-2026-3543 , EUVD-2026-30612
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 23%
- public exploits
- 0
- none known
Summary
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI allows admins to restrict which API endpoints an API key can access. When an API key is restricted from /api/v1/messages, requests using the Authorization: Bearer sk-... header are correctly blocked with 403. However, the same key sent via the x-api-key header bypasses the restriction entirely — the request is authenticated, the model is invoked, and a full response is returned. This vulnerability is fixed in 0.9.0.
Patch / fix
- pypi open-webui 0.9.0
- openwebui open_webui 0.9.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 5 mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/open-webui/open-webui/security/advisories/GHSA-57q6-fvp4-pqmm 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:H/UI:N/S:U/C:H/I:H/A:N |
| OSV | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | open-webui | <0.9.0 |
0.9.0 |
Affected products
- open-webui open-webui
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
github.com
/open-webui/open-webui/security/advisories/GHSA-57q6-fvp4-pqmm
exploit, web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-45339
advisory
-
github.com
/advisories/GHSA-57q6-fvp4-pqmm
advisory
-
github.com
/open-webui/open-webui
package
-
github.com
/open-webui/open-webui/releases/tag/v0.9.0
web
-
github.com
/pypa/advisory-database/tree/main/vulns/open-webui/PYSEC-2026-3543.yaml
web
-
pypi.org
/project/open-webui
web, package
Sources
- CVE List CVE-2026-45339
- GitHub Advisory GHSA-57q6-fvp4-pqmm
- NVD CVE-2026-45339
- OSV PYSEC-2026-3543
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.