Vulnerability record · CVE-2026-50178 · published 22 June 2026
CVE-2026-50178: Angular language service cross-site scripting vulnerability
Angular · Angular Language Service
The Angular Language Service VS Code Extension provides a rich editing experience for Angular templates. the client-side Angular Language Service VS Code extension configures the tooltip Markdown renderer with the isTrusted: true option (located in client/src/client.ts). This setting instructs VS Code to trust all rendered content it receives, which enables active elements such as command: URIs. However, the background Angular Language Server process fails to escape or sanitize brackets, raw links, and control characters from JSDoc strings before forwarding the hover Markdown content (located in server/src/handlers/hover.ts and server/src/text_render.ts). An attacker can leverage this behavior by crafting a project TypeScript or JavaScript file (or a third-party npm package dependency) containing a malicious JSDoc tooltip with an embedded active command link. When a developer hovers over the target symbol to render the tooltip and clicks the malicious link, the IDE executes the command sequence directly on the developer's host machine. Prior to 21.2.4, This vulnerability is fixed in 21.2.4.
Description
The Angular Language Service VS Code Extension provides a rich editing experience for Angular templates. the client-side Angular Language Service VS Code extension configures the tooltip Markdown renderer with the isTrusted: true option (located in client/src/client.ts). This setting instructs VS Code to trust all rendered content it receives, which enables active elements such as command: URIs. However, the background Angular Language Server process fails to escape or sanitize brackets, raw links, and control characters from JSDoc strings before forwarding the hover Markdown content (located in server/src/handlers/hover.ts and server/src/text_render.ts). An attacker can leverage this behavior by crafting a project TypeScript or JavaScript file (or a third-party npm package dependency) containing a malicious JSDoc tooltip with an embedded active command link. When a developer hovers over the target symbol to render the tooltip and clicks the malicious link, the IDE executes the command sequence directly on the developer's host machine. Prior to 21.2.4, This vulnerability is fixed in 21.2.4.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://github.com/angular/angular/security/advisories/GHSA-q94j-3wj3-4xcm | Vendor Advisory |
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-50178), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.