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.

Project Subscriptions

Vendors Products
Eclipse Subscribe
Open Vsx Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 23 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Eclipse
Eclipse open Vsx
Vendors & Products Eclipse
Eclipse open Vsx

Tue, 23 Jun 2026 12:30:00 +0000

Type Values Removed Values Added
Title Malicious SVG Icons Leading to Stored XSS in Eclipse Open VSX
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 23 Jun 2026 11:45:00 +0000

Type Values Removed Values Added
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.
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: eclipse

Published:

Updated: 2026-06-23T12:03:13.663Z

Reserved: 2026-03-27T12:31:27.749Z

Link: CVE-2026-4983

cve-icon Vulnrichment

Updated: 2026-06-23T12:03:09.532Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-23T14:15:04Z

Weaknesses