CVE-2026-65675: VS Code Copilot Auth Bypass Vulnerability

CVE-2026-65675 Overview

CVE-2026-65675 is a security feature bypass vulnerability affecting the Visual Studio Code CoPilot Chat Extension. An unauthorized attacker can bypass a security feature over a network when a user interacts with attacker-controlled content. The flaw is classified under [CWE-284] Improper Access Control and carries a CVSS 3.1 base score of 7.1. Successful exploitation requires user interaction but no authentication. Microsoft published the advisory on August 11, 2026.

Critical Impact
Attackers can bypass access control mechanisms in the CoPilot Chat Extension, undermining integrity and enabling downstream compromise of developer workflows.

Affected Products

Microsoft Visual Studio Code CoPilot Chat Extension
Developer environments with the CoPilot Chat Extension enabled
Integrated development workflows using CoPilot Chat features

Discovery Timeline

2026-08-11 - CVE CVE-2026-65675 published to NVD
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2026-65675

Vulnerability Analysis

The vulnerability resides in the Visual Studio Code CoPilot Chat Extension. It enables an unauthorized attacker to bypass a security feature over the network. The issue is classified as [CWE-284] Improper Access Control. Exploitation requires user interaction, such as opening or engaging with attacker-controlled content in the extension. The attack can be launched remotely without valid credentials on the target system. Successful exploitation results in high integrity impact, with limited availability impact and no direct confidentiality impact. The EPSS probability is 0.481% at the 39th percentile, indicating low observed exploitation likelihood at publication.

Root Cause

The root cause is improper access control within the CoPilot Chat Extension. Access decisions are not enforced consistently, allowing an unauthorized actor to bypass an intended security check. Microsoft has not disclosed additional internal implementation details in the public advisory.

Attack Vector

The attack vector is network-based. An attacker delivers crafted content, prompts, or resources that the extension processes when a user interacts with it. Because the bypass targets integrity, an attacker may cause the extension to perform actions or accept inputs that should have been blocked. See the Microsoft Security Advisory for vendor guidance.

Detection Methods for CVE-2026-65675

Indicators of Compromise

Unexpected CoPilot Chat Extension activity following user interaction with untrusted repositories, files, or chat content.
Modifications to developer workflow artifacts, configuration files, or source code that do not correspond to authorized user actions.
Outbound network connections from the VS Code process to unfamiliar domains after CoPilot Chat sessions.

Detection Strategies

Monitor process telemetry for anomalous child processes or file writes originating from Visual Studio Code following CoPilot Chat interactions.
Inspect installed extension versions across managed developer endpoints and flag unpatched CoPilot Chat Extension builds.
Correlate developer endpoint activity with network traffic to identify content sources that trigger extension misuse.

Monitoring Recommendations

Enable endpoint logging for VS Code and its extension host processes, capturing command execution and file system changes.
Track extension installation, update, and configuration events across the developer fleet.
Alert on integrity-impacting actions such as unexpected git operations, credential file access, or workspace configuration changes.

How to Mitigate CVE-2026-65675

Immediate Actions Required

Update the Visual Studio Code CoPilot Chat Extension to the fixed version identified in the Microsoft Security Advisory.
Restrict CoPilot Chat usage against untrusted repositories, files, or third-party content until the patch is deployed.
Educate developers to avoid interacting with untrusted prompts, links, or workspaces served through the extension.

Patch Information

Microsoft has released updated builds of the Visual Studio Code CoPilot Chat Extension. Apply the vendor-provided update through the Visual Studio Code Marketplace. Refer to the Microsoft Security Advisory for version details and deployment guidance.

Workarounds

Disable the CoPilot Chat Extension on endpoints where the patch cannot be applied immediately.
Enforce Workspace Trust in Visual Studio Code and require explicit user approval before opening untrusted folders.
Limit extension execution to vetted workspaces via enterprise policy configuration until the update is validated.

bash

# Configuration example: update or disable the extension via CLI
code --install-extension GitHub.copilot-chat --force
code --disable-extension GitHub.copilot-chat