Open WebUI: Stored XSS in Pending User Overlay via Incorrect DOMPurify Application Order
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the AccountPending.svelte component renders the admin-configured "Pending User Overlay Content" using marked.parse() inside {@html} with an incorrect DOMPurify application order. An admin can inject arbitrary JavaScript into the Pending User Overlay Content that executes in the browser context of any pending user who views the overlay page. This vulnerability is fixed in 0.9.0.
- Published
- May 15, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.3% · 15th percentile
- CWE
- CWE-79
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Report tools
Action score
19
Monitor
Low priority for now.
- CVSS
- 19 / 40 · 4.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 4.8
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| openwebui | open webui | cpe:2.3:a:openwebui:open_webui |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- openwebui open webuibefore 0.9.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
open-webui open-webui
- < 0.9.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| PyPI | open-webui | before 0.9.0 | 0.9.0 |
Same product
openwebui: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-44566Open WebUI: Arbitrary File Upload and Path Traversal39Monitor
- CVE-2026-56400open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation36Monitor
- CVE-2026-59216Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id36Monitor
- CVE-2026-59214Open WebUI: Stored web worker XSS via Pyodide36Monitor
- CVE-2026-44551Open WebUI: LDAP Empty Password Authentication Bypass36Monitor
- CVE-2024-8017Cross-site Scripting (XSS) in open-webui/open-webui36Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| open-webui open-webui | 0.9.0 · description | Vendor (CNA) |
| PyPI:open-webui | 0.9.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-5921455 days apartOpen WebUI: Stored web worker XSS via Pyodide36Monitor
- CVE-2024-8017421 days apartCross-site Scripting (XSS) in open-webui/open-webui36Monitor
- CVE-2024-7044421 days apartStored XSS in open-webui/open-webui35Monitor
- CVE-2026-445490 days apartOpen WebUI: Stored XSS in excel file preview34Monitor
- CVE-2026-453150 days apartOpen WebUI: Stored XSS via attacker-controlled file extension in /api/v1/audio/transcriptions34Monitor
- CVE-2026-87995117 days apartOpen WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin34Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- Administrator privileges are required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- low · data or configuration can be modified
- Availability
- none
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- Required
- Scope
- Changed
- Confidentiality impact
- Low
- Integrity impact
- Low
- Availability impact
- None
Weakness class (CWE)
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
nvd-secondary
Root cause
User content is inserted into the page as HTML. The browser interprets the content as code rather than data.
The bug in code
The whole CWE-79 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
commentEl.innerHTML = comment.body;Fixed
commentEl.textContent = comment.body;Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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