“`html
Critical Open VSX Registry Vulnerability Exposes VS Code Extensions to Supply Chain Attacks
Table of Contents
A severe vulnerability discovered in the Open VSX Registry, a popular open-source alternative to the Visual Studio Marketplace, could have given malicious actors complete control over the distribution of Visual Studio Code (VS Code) extensions. If exploited, this flaw woudl have presented a significant supply chain risk, perhaps impacting millions of developers.
Marketplace Takeover: How the Open VSX Vulnerability Worked
According to Koi security researcher Oren Yomtov, the vulnerability allowed attackers to publish malicious updates to any extension on Open VSX by exploiting a Continuous Integration (CI) issue. This could have resulted in the compromise of countless developer machines. The vulnerability was responsibly disclosed on May 4, 2025, and a final patch was implemented by the maintainers on June 25, 2025.
Did You Know? The Eclipse Foundation maintains the Open VSX registry, which is integrated into several code editors, including Google Cloud Shell Editor and gitpod.
The Technical details of the Open VSX Exploit
The vulnerability stemmed from the publish-extensions repository, which houses scripts designed to publish open-source VS Code extensions to open-vsx.org.The process involves developers submitting a pull request to add their extension to the extensions.json file within the repository. Once approved, a github Actions workflow, running daily, publishes the extensions to the registry using the vsce npm package.
This workflow operates with elevated privileges, utilizing a secret token (OVSX_PAT) belonging to the @open-vsx service account.This token grants the ability to publish or overwrite any extension within the marketplace. the core issue was that `npm install` executed arbitrary build scripts of all auto-published extensions and their dependencies, granting them access to the sensitive OVSX_PAT surroundings variable.
Pro Tip: Regularly audit your VS code extensions and their dependencies to identify and mitigate potential security risks.
The Supply Chain Nightmare Scenario
The widespread adoption of Open VSX makes it a prime target for supply chain attacks. Each extension installation or update goes through Open VSX, meaning a compromise could have far-reaching consequences. Attackers could potentially gain access to the @open-vsx account’s token, enabling them to publish malicious extensions or tamper with existing ones.
MITRE Recognizes the Threat of IDE Extensions
The MITRE ATT&CK framework acknowledged the growing risk of extension-based attacks by introducing a new “
