CVE-2026-4983
Open VSX Registry Stored Cross-Site Scripting via Malicious SVG Icons
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.
INFO
Published Date :
June 23, 2026, 12:16 p.m.
Last Modified :
June 24, 2026, 4:55 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | e51fbebd-6053-4e49-959f-1b94eeb69a2c | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Sanitize all uploaded SVG files.
- Serve SVGs with Content-Security-Policy header.
- Serve SVGs with Content-Disposition: attachment header.
- Update to the latest version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-4983.
| URL | Resource |
|---|---|
| https://gitlab.eclipse.org/security/cve-assignment/-/work_items/91 | Issue Tracking Vendor Advisory Exploit |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-4983 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-4983
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-4983 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-4983 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 24, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:eclipse:open_vsx:*:*:*:*:*:*:*:* versions from (including) 0.1.0 up to (excluding) 0.34.1 Added Reference Type Eclipse Foundation: https://gitlab.eclipse.org/security/cve-assignment/-/work_items/91 Types: Exploit, Issue Tracking, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-4983', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-23T12:02:52.330281Z'} -
New CVE Received by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/eclipse-openvsx/openvsx', 'vendor': 'Eclipse Foundation', 'product': 'Eclipse Open VSX', 'versions': [{'status': 'affected', 'version': '0.1.0', 'lessThan': '0.34.1', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N Added CWE CWE-79 Added Reference https://gitlab.eclipse.org/security/cve-assignment/-/work_items/91