Vulnerability Description
Open VSX Registry does not sanitize SVG files uploaded as extension icons prior to storage, and serves them with Content-Type: image/svg+xml without security headers such as Content-Security-Policy or Content-Disposition: attachment. This allows an attacker to publish an extension with a malicious SVG icon and achieve stored cross-site scripting (XSS) when a user navigates directly to the icon URL. On deployments using local storage, script execution occurs within the Open VSX application origin, enabling session hijacking, authentication token theft, and unauthorized extension publishing. On deployments backed by external storage (such as open-vsx.org with an S3-backed CDN), execution is confined to the storage origin, reducing impact but still permitting phishing attacks and credential harvesting through attacker-crafted pages.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Eclipse | Open Vsx | >= 0.1.0, < 0.34.1 |
Related Weaknesses (CWE)
References
- https://gitlab.eclipse.org/security/cve-assignment/-/work_items/91Issue TrackingVendor AdvisoryExploit
FAQ
What is CVE-2026-4983?
CVE-2026-4983 is a vulnerability with a CVSS score of 4.1 (MEDIUM). Open VSX Registry does not sanitize SVG files uploaded as extension icons prior to storage, and serves them with Content-Type: image/svg+xml without security headers such as Content-Security-Policy or...
How severe is CVE-2026-4983?
CVE-2026-4983 has been rated MEDIUM with a CVSS base score of 4.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-4983?
Check the references section above for vendor advisories and patch information. Affected products include: Eclipse Open Vsx.