WhatsApp Web users should update their Google Chrome extensions after Pakistan’s National Cyber Emergency Response Team (National CERT) warned about a security vulnerability in the Adobe Acrobat PDF extension.
The vulnerability, tracked as CVE-2026-48294, affects Adobe Acrobat PDF Extension for Chrome versions 26.5.2.2 and earlier. The National Vulnerability Database (NVD) gives the flaw a 7.4 High severity rating.
Pakistan’s National CERT has also listed the issue in its 2026 advisories as “Adobe Acrobat Chrome Extension Vulnerability Exposing WhatsApp Web Sessions.”
The flaw does not come from WhatsApp itself. Instead, attackers can exploit the vulnerable Adobe Acrobat extension when a user has an active WhatsApp Web session in Chrome.
How the Chrome Vulnerability Can Expose WhatsApp Data
Security researchers classify CVE-2026-48294 as a UXSS-class cross-origin data disclosure vulnerability.
The attack requires user interaction. A victim must visit a specially crafted malicious website or interact with a compromised webpage while Chrome runs the affected Adobe Acrobat extension. NVD confirms that the attack requires the victim to open a malicious URL or interact with a compromised webpage.
Under the right conditions, the malicious website can exploit the extension and access information from an active WhatsApp Web session.
Researchers found that the attack could expose information such as:
- WhatsApp chat lists
- Contact and group names
- Message previews
- Messages from an open conversation
- WhatsApp profile information
- Other information displayed in the active WhatsApp Web session
The attack does not require the victim to provide a WhatsApp password. It also does not require attackers to install traditional malware on the computer.
Which Adobe Acrobat Versions Does the Flaw Affect?
CVE-2026-48294 affects Adobe Acrobat PDF Extension for Chrome versions 26.5.2.2 and earlier. NVD lists the vulnerability as High severity with a CVSS score of 7.4.
Security researchers at Guardio Labs named the vulnerability HermeticReader. The flaw affects the extension’s integration with WhatsApp Web and its handling of content across different web origins.
Adobe Released a Security Fix
Adobe fixed the vulnerability in version 26.5.2.3 of the Acrobat PDF Chrome extension. Users should still install the latest version available through Chrome rather than relying on an older fixed release.
Users should check their extension version and update it immediately if they still run an affected release.
Researchers have described the vulnerability as a serious privacy risk, but available reporting does not indicate confirmed widespread exploitation of CVE-2026-48294. NVD’s CISA assessment also currently lists exploitation as none.
How to Check the Adobe Acrobat Chrome Extension
Chrome users can check their extension by following these steps:
- Open Google Chrome.
- Enter chrome://extensions in the address bar.
- Find the Adobe Acrobat extension.
- Check the installed version.
- Update the extension if it runs 26.5.2.2 or earlier.
Users who do not need the extension can also remove it from Chrome to reduce their browser’s attack surface.
WhatsApp Users Should Check Linked Devices
Users who suspect unusual activity should review their WhatsApp Linked Devices.
Open WhatsApp, select Linked Devices, and check the connected browsers and computers. Log out of any device that you do not recognize or no longer use.
Users should also avoid suspicious websites and unexpected links from unknown sources. A malicious webpage can provide the trigger that the vulnerability requires.
Organizations Should Review Chrome Extensions
Organizations that use WhatsApp Web should check their managed Chrome installations for vulnerable Adobe Acrobat extensions.
IT teams should maintain an inventory of browser extensions, remove unnecessary extensions and install security updates promptly.
Organizations should also investigate unusual browser activity and preserve relevant browser and network logs when they suspect a security incident.
Is WhatsApp Itself Vulnerable?
No. CVE-2026-48294 affects the Adobe Acrobat Chrome extension, not WhatsApp’s core application.
The vulnerability can expose information from an active WhatsApp Web session because the malicious webpage can abuse the vulnerable browser extension. Researchers did not identify the issue as a weakness in WhatsApp’s end-to-end encryption.
What WhatsApp Web Users Should Do
WhatsApp Web users should take these steps:
- Update the Adobe Acrobat Chrome extension immediately.
- Update Google Chrome to the latest available version.
- Remove unnecessary browser extensions.
- Avoid suspicious websites and unknown links.
- Review WhatsApp Linked Devices regularly.
- Log out of unfamiliar WhatsApp Web sessions.
- Keep Chrome and all browser extensions updated.
CVE-2026-48294 carries a 7.4 High severity rating, and NVD confirms that Adobe Acrobat PDF Extension for Chrome versions 26.5.2.2 and earlier contain the vulnerability.
For WhatsApp Web users, the most important step remains simple: check the Adobe Acrobat Chrome extension and update it immediately if it runs an affected version.
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