GitHub said late Tuesday that internal repositories were exfiltrated after an employee device was compromised through a poisoned Visual Studio Code extension, an incident that underscores the growing risks facing software development platforms and the ecosystems built around third-party developer tools.

The Microsoft-owned company said in posts on X that it detected and contained the compromise, removed the malicious extension version, isolated the affected endpoint and began an incident response investigation. The company’s current assessment is that the activity involved GitHub-internal repositories only.

GitHub also said a claim from TeamPCP, a hacking group behind attacks targeting software development packages, that 3,800 repositories were impacted was “directionally consistent” with its investigation so far. It said critical secrets were rotated Tuesday, with the highest-impact credentials prioritized first. The company said it continued to analyze logs, validate secret rotation and monitor for follow-on activity.

The company has not publicly named the extension involved or attributed the activity to a particular group. TeamPCP reportedly advertised the material for sale on a cybercrime forum and threatened to release it if no buyer emerged. 

Information surfaced Wednesday that the incident may be related to a separate issue with Nx Console, a Visual Studio Code tool that helps engineering teams organize large codebases, coordinate build pipelines and run tests efficiently. According to a security advisory posted on GitHub, one of the Nx Console maintainers was compromised in a prior security incident that leaked their GitHub credentials. An attack then used those credentials to push a malicious version of the extension to the VS Code Marketplace. Those credentials have since been temporarily revoked.

With millions of installs, Nx Console is a fixture of professional JavaScript development. It is exactly the kind of tool that sits deep inside a developer’s working environment, which would have direct access to source code, credentials and build systems.

NX CEO Jeff Cross posted on X Wednesday that his company has been working with Microsoft to determine the full scope of the incident.

“Initially, Microsoft indicated to us that there were 28 installs of the malicious version 18.95.0. Based on our own analytics for the compromised version, we currently believe the number of users who received the malicious package may be significantly higher; potentially over 6k installs,” the post reads.

“This is my top priority right now,” Cross continued. “Our team has been, and continues to be focused on understanding exactly what happened, helping affected users, hardening our systems and release processes, and being as transparent as possible throughout the investigation.”

The episode also follows a series of supply chain attacks involving npm, PyPI, Docker and other developer ecosystems. In those incidents, attackers have often targeted maintainers, packages or credentials rather than attacking end users directly. The multiple attacks show how fragile development environments have become as threat actors increasingly target them. A single compromised developer account, package, extension or build process can create access to many downstream systems.

GitHub has said it has no evidence that customer data stored outside the affected repositories was affected.

Visual Studio Code extensions are widely used by developers to add functions to Microsoft’s code editor, including support for programming languages, testing tools, cloud services and artificial intelligence assistants. Because these extensions often operate inside development environments, a malicious or compromised extension can be positioned close to source code, credentials and build systems.

“The thing people underestimate about VS Code extensions is that they have full access to everything on the developer’s machine,” Charlie Eriksen, a security researcher at Aikido Security, told CyberScoop. “EDR doesn’t cover this layer at all. What’s missing for most organisations is any kind of visibility into what’s actually running on developer machines and the ability to control it.”

Trojanized extensions have appeared in the VS Code Marketplace before. Security researchers have identified malicious extensions posing as legitimate development tools, including packages used to steal credentials, mine cryptocurrency or exfiltrate data. Some have accumulated large installation counts before removal, reflecting the difficulty of policing open plugin ecosystems at scale.

For GitHub, the breach comes amid broader scrutiny of the security of developer infrastructure. The platform sits at the center of software production for companies, governments, open-source maintainers and independent developers. Its internal systems and code are of obvious interest to attackers because GitHub’s services support code hosting, package distribution, automation and identity workflows across much of the software industry.

GitHub said it would publish a fuller report when the investigation is complete.

Update: May 20, 12:55 p.m.: This story has been updated with information about a related security incident with Nx Console.

The post GitHub says internal repositories were impacted in poisoned VS Code extension attack appeared first on CyberScoop.

Microsoft this week pushed security updates to fix more than 60 vulnerabilities in its Windows operating systems and supported software, including at least one zero-day bug that is already being exploited. Microsoft also fixed a glitch that prevented some Windows 10 users from taking advantage of an extra year of security updates, which is nice because the zero-day flaw and other critical weaknesses affect all versions of Windows, including Windows 10.

Affected products this month include the Windows OS, Office, SharePoint, SQL Server, Visual Studio, GitHub Copilot, and Azure Monitor Agent. The zero-day threat concerns a memory corruption bug deep in the Windows innards called CVE-2025-62215. Despite the flaw’s zero-day status, Microsoft has assigned it an “important” rating rather than critical, because exploiting it requires an attacker to already have access to the target’s device.

“These types of vulnerabilities are often exploited as part of a more complex attack chain,” said Johannes Ullrich, dean of research for the SANS Technology Institute. “However, exploiting this specific vulnerability is likely to be relatively straightforward, given the existence of prior similar vulnerabilities.”

Ben McCarthy, lead cybersecurity engineer at Immersive, called attention to CVE-2025-60274, a critical weakness in a core Windows graphic component (GDI+) that is used by a massive number of applications, including Microsoft Office, web servers processing images, and countless third-party applications.

“The patch for this should be an organization’s highest priority,” McCarthy said. “While Microsoft assesses this as ‘Exploitation Less Likely,’ a 9.8-rated flaw in a ubiquitous library like GDI+ is a critical risk.”

Microsoft patched a critical bug in Office — CVE-2025-62199 — that can lead to remote code execution on a Windows system. Alex Vovk, CEO and co-founder of Action1, said this Office flaw is a high priority because it is low complexity, needs no privileges, and can be exploited just by viewing a booby-trapped message in the Preview Pane.

Many of the more concerning bugs addressed by Microsoft this month affect Windows 10, an operating system that Microsoft officially ceased supporting with patches last month. As that deadline rolled around, however, Microsoft began offering Windows 10 users an extra year of free updates, so long as they register their PC to an active Microsoft account.

Judging from the comments on last month’s Patch Tuesday post, that registration worked for a lot of Windows 10 users, but some readers reported the option for an extra year of updates was never offered. Nick Carroll, cyber incident response manager at Nightwing, notes that Microsoft has recently released an out-of-band update to address issues when trying to enroll in the Windows 10 Consumer Extended Security Update program.

“If you plan to participate in the program, make sure you update and install KB5071959 to address the enrollment issues,” Carroll said. “After that is installed, users should be able to install other updates such as today’s KB5068781 which is the latest update to Windows 10.”

Chris Goettl at Ivanti notes that in addition to Microsoft updates today, third-party updates from Adobe and Mozilla have already been released. Also, an update for Google Chrome is expected soon, which means Edge will also be in need of its own update.

The SANS Internet Storm Center has a clickable breakdown of each individual fix from Microsoft, indexed by severity and CVSS score. Enterprise Windows admins involved in testing patches before rolling them out should keep an eye on askwoody.com, which often has the skinny on any updates gone awry.

As always, please don’t neglect to back up your data (if not your entire system) at regular intervals, and feel free to sound off in the comments if you experience problems installing any of these fixes.

[Author’s note: This post was intended to appear on the homepage on Tuesday, Nov. 11. I’m still not sure how it happened, but somehow this story failed to publish that day. My apologies for the oversight.]