Session Fixation / Privilege Escalation in Visual Studio Code MCP One-Click Installer
CVE-2026-41613 is an elevation of privilege vulnerability in Microsoft Visual Studio Code affecting the one-click installer flow for Model Context Protocol (MCP) servers. According to the provided reporting, the installer preview dialog displayed only a subset of the configuration fields while silently accepting additional hidden fields, including environment variables and HTTP headers. This UI trust-boundary failure allowed a malicious MCP install link or malicious file opened in VS Code to present an apparently benign installation prompt while injecting unseen configuration. One exploitation path abused hidden environment-variable injection, specifically NODE_OPTIONS, together with Node.js --import support for data URLs, to preload attacker-controlled JavaScript before the MCP server started; that JavaScript could then execute shell commands permitted by the host OS. A second path abused hidden HTTP headers so the MCP server authenticated using attacker-supplied credentials, causing subsequent assistant actions to execute within the attacker-controlled session. Microsoft classifies the issue as session fixation and associates it with Visual Studio Code privilege escalation over a network.
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Impact, mitigation & remediation
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Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
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Exploits
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No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
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A Visual Studio Code vulnerability in the one-click MCP server installer that allowed hidden fields such as environment variables and HTTP headers to be supplied without being shown in the install confirmation UI, enabling arbitrary JavaScript/code execution via NODE_OPTIONS --import and credential/session hijacking.
A Visual Studio Code vulnerability included in a cluster of fixes affecting VSCode, covering issues such as elevation of privilege, information disclosure, remote code execution, and security feature bypass. The specific flaw type for this CVE is not individually identified in the content.
A session fixation vulnerability in Visual Studio Code that allows an unauthorized attacker to elevate privileges over a network.
An elevation of privilege vulnerability in Visual Studio Code involving session fixation that can allow an unauthorized attacker over a network to gain the permissions associated with the MCP Server’s managed identity if a user opens a malicious file.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.