PT-2026-51488 · Eclipse Foundation · Eclipse Open Vsx

Golan Myers · Published 2026-06-23 · Updated 2026-06-23 · CVE-2026-4983

NVD

CVSS v3.1

4.1

Medium

Base vector

AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N

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.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-4983

Affected Products

Eclipse Open Vsx

References · 2

• https://nvd.nist.gov/vuln/detail/CVE-2026-4983 · Security Note
• https://gitlab.eclipse.org/security/cve-assignment/-/work_items/91 · Note