Vercel breach exposes the OAuth gap most security teams cannot detect, scope or contain

One employee at Vercel adopted an AI tool. One employee at that AI vendor got hit with an infostealer. That combination created a walk-in path to Vercel’s production environments through an OAuth grant that nobody had reviewed.

Vercel, the cloud platform behind Next.js and its millions of weekly npm downloads, confirmed on Sunday that attackers gained unauthorized access to internal systems. Mandiant was brought in. Law enforcement was notified. Investigations remain active. An update on Monday confirmed that Vercel collaborated with GitHub, Microsoft, npm, and Socket to verify that no Vercel npm packages were compromised. Vercel also announced it is now defaulting environment variable creation to “sensitive.” Next.js, Turbopack, AI SDK, and all Vercel-published npm packages remain uncompromised after a coordinated audit with GitHub, Microsoft, npm, and Socket.

Context.ai was the entry point. OX Security’s analysis found that a Vercel employee installed the Context.ai browser extension and signed into it using a corporate Google Workspace account, granting broad OAuth permissions. When Context.ai was breached, the attacker inherited that employee’s Workspace access, pivoted into Vercel environments, and escalated privileges by sifting through environment variables not marked as “sensitive.” Vercel’s bulletin states that variables marked sensitive are stored in a manner that prevents them from being read. Variables without that designation were accessible in plaintext through the dashboard and API, and the attacker used them as the escalation path.

CEO Guillermo Rauch described the attacker as “highly sophisticated and, I strongly suspect, significantly accelerated by AI.” Jaime Blasco, CTO of Nudge Security, independently surfaced a second OAuth grant tied to Context.ai’s Chrome extension, matching the client ID from Vercel’s published IOC to Context.ai’s Google account before Rauch’s public statement. The Hacker News reported that Google removed Context.ai’s Chrome extension from the Chrome Web Store on March 27. Per The Hacker News and Nudge Security, that extension embedded a second OAuth grant enabling read access to users’ Google Drive files.

Patient zero. A Roblox cheat and a Lumma Stealer infection

Hudson Rock published forensic evidence on Monday, reporting that the breach origin traces to a February 2024 Lumma Stealer infection on a Context.ai employee’s machine. According to Hudson Rock, browser history showed the employee downloading Roblox auto-farm scripts and game exploit executors. Harvested credentials included Google Workspace logins, Supabase keys, Datadog tokens, Authkit credentials, and the [email protected] account. Hudson Rock identified the infected user as a core member of “context-inc,” Context.ai’s tenant on the Vercel platform, with administrative access to production environment variable dashboards.

Context.ai published its own bulletin on Sunday (updated Monday), disclosing that the breach affects its deprecated AI Office Suite consumer product, not its enterprise Bedrock offering. Context.ai says it detected unauthorized access to its AWS environment in March, hired CrowdStrike to investigate, and shut down the environment. Its updated bulletin then disclosed that the scope was broader than initially understood: the attacker also compromised OAuth tokens for consumer users, and one of those tokens opened the door to Vercel’s Google Workspace.

Dwell time is the detail that should concern security directors. Nearly a month separated Context.ai’s March detection from the Vercel disclosure on Sunday. A separate Trend Micro analysis references an intrusion beginning as early as June 2024 — a finding that, if confirmed, would extend the dwell time significantly.

Six governance failures the Vercel breach exposed

1. AI tool OAuth scopes go unaudited. Context.ai’s own bulletin states that a Vercel employee granted “Allow All” permissions using a corporate account. Most security teams have no inventory of which AI tools their employees have granted OAuth access to.

2. Environment variable classification is doing real security work. Vercel distinguishes between variables marked “sensitive” and those without that designation. Attackers used the accessible variables as the escalation path. Vercel has since changed its default: new environment variables now default to sensitive.

3. Infostealer-to-SaaS-to-supply-chain escalation chains lack detection coverage. Hudson Rock’s reporting reveals a kill chain that crossed four organizational boundaries, highlighting a massive gap in modern security stacks.