Adobe Chrome Extension Flaw Exposed WhatsApp Web Data, Now Fixed

Israeli cybersecurity firm Guardio discovered a critical vulnerability in the Adobe Acrobat Reader extension for the Chrome browser, which is installed on over 300 million computers worldwide. The flaw allowed attackers to access sensitive information from WhatsApp Web, including chat lists, contact names, profile pictures, on-screen messages, and one-time digital codes. These codes could potentially enable breaches of additional accounts such as Instagram and Facebook.

The attack scenario demonstrated by Guardio did not require hacking WhatsApp directly, stealing passwords, or installing malware. Instead, it relied on victims clicking a malicious link that appeared legitimate, which could be delivered via SMS, email, WhatsApp messages, Slack, Microsoft Teams, or even through sponsored Google search results. Once the link was opened, the vulnerability in the Adobe extension could be exploited within less than a second to access WhatsApp Web data in the same browser.

Guardio reported the vulnerability to Adobe through a responsible disclosure process. Adobe confirmed the findings, promptly fixed the security flaw within days, and released an update to users, making the exploit no longer possible. There have been no reports of users being harmed by this vulnerability.

Guardio’s research head, Nati Tal, emphasized how the proliferation of tools, browser extensions, and AI systems with direct access to personal data expands the attack surface for cybercriminals. He noted that attackers often target the weakest link in the surrounding environment rather than the primary service itself. Tal also highlighted that advanced AI models, like those from Anthropic, enable rapid and extensive code vulnerability searches, which can be a double-edged sword if such tools fall into the wrong hands. Guardio’s AI-driven research system identified the flaw within hours of the vulnerable extension’s release on the Chrome Web Store.