Skip to content

URL unicode escaping

High
connor4312 published GHSA-g84c-g4wq-2pwp Feb 10, 2026

Package

Github.copilot-chat (Visual Studio Code Marketplace)

Affected versions

<0.37.3

Patched versions

0.37.3

Description

VS Code - Remote Code Execution Vulnerability

A remote code execution vulnerability exists in VS Code Copilot Chat 0.37.2 and earlier versions where a prompt-injected agent could ask the user to open or fetch malicious URLs with look-alike characters to trusted URLs.

Patches

The fix is available starting with VS Code Copilot Chat 0.37.3. The fix mitigates this attack by punycode encoding URLs appropriately when presenting them to the user.

Workarounds

Do not approve fetch requests or open URLs from agent sessions which may have been subject to prompt injection attacks in Copilot Chat version 0.37.2 or earlier.

References

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CVE ID

CVE-2026-21523

Weaknesses

No CWEs