CVE-2026-78461: Visual Studio Code Path Traversal Flaw

CVE-2026-78461 Overview

CVE-2026-78461 is a path traversal vulnerability in Microsoft Visual Studio Code that allows an unauthorized attacker to bypass a security feature over a network. The flaw is classified under [CWE-22], improper limitation of a pathname to a restricted directory. Exploitation requires user interaction, and a successful attack results in a scope change with high confidentiality impact.

Critical Impact
An unauthenticated remote attacker can bypass a Visual Studio Code security boundary through crafted path inputs, exposing sensitive information outside the intended restricted directory.

Affected Products

Microsoft Visual Studio Code

Discovery Timeline

2026-09-08 - CVE-2026-78461 published to the National Vulnerability Database
2026-09-09 - Last updated in NVD database

Technical Details for CVE-2026-78461

Vulnerability Analysis

The vulnerability stems from improper limitation of a pathname to a restricted directory within Visual Studio Code. An attacker who convinces a user to interact with attacker-controlled content can traverse outside the intended sandboxed directory. The result is a security feature bypass that crosses a trust boundary, indicated by the scope change in the CVSS vector. The impact is limited to confidentiality; integrity and availability are not directly affected.

Because Visual Studio Code processes workspaces, extensions, and remote resources containing file paths, path traversal weaknesses can allow attacker-supplied paths to reach files or resources the editor is meant to isolate. This class of flaw is tracked as [CWE-22].

Root Cause

The root cause is insufficient normalization and validation of pathname inputs before they are resolved against a restricted directory. Sequences such as ../ or encoded equivalents are not adequately filtered, allowing resolution to escape the intended base directory. Microsoft has not published low-level implementation details in the public advisory.

Attack Vector

The attack vector is network-based and requires user interaction, such as opening a crafted workspace, project, repository, or file supplied by the attacker. No privileges or prior authentication are required. When the user opens the malicious content, Visual Studio Code resolves the manipulated path, bypassing the intended directory restriction and exposing protected resources to the attacker-controlled context.

Refer to the Microsoft Security Update Guide for CVE-2026-78461 for vendor technical details.

Detection Methods for CVE-2026-78461

Indicators of Compromise

Workspace, repository, or project files containing suspicious path segments such as ../, ..\, or URL-encoded traversal sequences (%2e%2e%2f).
Visual Studio Code processes reading files outside the opened workspace root shortly after a user opens an untrusted project.
Unexpected outbound network connections from Code.exe or code following the opening of a newly cloned repository.

Detection Strategies

Inspect endpoint telemetry for Code.exe or code accessing sensitive paths (user profile, SSH keys, credential stores) that fall outside the active workspace directory.
Hunt across code repositories and shared project archives for files whose paths contain traversal patterns or encoded traversal sequences.
Correlate Visual Studio Code extension installation events with subsequent anomalous file reads across trust boundaries.

Monitoring Recommendations

Enable file access auditing on directories that hold credentials, tokens, and configuration files, and alert when the Visual Studio Code process reads them.
Monitor Visual Studio Code update channels to confirm timely deployment of the vendor patch across the environment.
Track user actions that dismiss Workspace Trust prompts, since exploitation depends on user interaction with untrusted content.

How to Mitigate CVE-2026-78461

Immediate Actions Required

Update Visual Studio Code to the patched version listed in the Microsoft Security Update Guide for CVE-2026-78461.
Instruct developers not to open untrusted repositories, workspaces, or project files received from external sources until patching is complete.
Audit installed Visual Studio Code extensions and remove any that are unmaintained or sourced from untrusted publishers.

Patch Information

Microsoft has published guidance and fixed builds through the Microsoft Security Update Guide for CVE-2026-78461. Apply the update through the built-in Visual Studio Code auto-update mechanism or your managed software distribution platform.

Workarounds

Enable and enforce Visual Studio Code Workspace Trust so untrusted folders open in a restricted mode that limits extension and task execution.
Restrict opening of workspaces to directories on vetted, controlled storage locations.
Use application allowlisting to prevent execution of Visual Studio Code builds older than the patched release.

bash

# Configuration example: enforce Workspace Trust in settings.json
{
  "security.workspace.trust.enabled": true,
  "security.workspace.trust.startupPrompt": "always",
  "security.workspace.trust.untrustedFiles": "prompt",
  "security.workspace.trust.banner": "always",
  "extensions.autoUpdate": true
}