CVE-2026-45318 json
Open WebUI: Stored XSS via unsanitized Office/Excel/DOCX file preview rendering ({@html} without DOMPurify)
published 2026-05-14 5 mo ago modified 2026-07-13 3 mo ago also EUVD-2026-30659 , GHSA-hcwp-82g6-8wxc , PYSEC-2026-2731
- cvss
- 5.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 11%
- public exploits
- 0
- none known
Summary
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, his advisory tracks a regression of the original Excel-preview XSS (CVE-2026-44549). The same root cause — XLSX.utils.sheet_to_html() output rendered via {@html excelHtml} without DOMPurify — was reintroduced sometime after v0.8.0 and is exploitable again This vulnerability is fixed in 0.9.3.
Patch / fix
- pypi open-webui 0.9.3
- openwebui open_webui 0.9.3
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/open-webui/open-webui/security/advisories/GHSA-hcwp-82g6-8wxc referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| GitHub | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| OSV | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | open-webui | <0.9.3 |
0.9.3 |
Affected products
- open-webui open-webui
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/open-webui/open-webui/security/advisories/GHSA-hcwp-82g6-8wxc
exploit, web, mitigation, vendor-advisory
-
github.com
/open-webui/open-webui/security/advisories/GHSA-jwf8-pv5p-vhmc
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-45318
advisory
-
github.com
/open-webui/open-webui
package
-
github.com
/open-webui/open-webui/releases/tag/v0.9.3
web
-
pypi.org
/project/open-webui
package
-
github.com
/advisories/GHSA-hcwp-82g6-8wxc
advisory
Sources
- CVE List CVE-2026-45318
- GitHub Advisory GHSA-hcwp-82g6-8wxc
- NVD CVE-2026-45318
- OSV PYSEC-2026-2731
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.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.