A cryptographic flaw in PDFium, the encrypted‑PDF rendering engine embedded in Google Chrome, allows an attacker to brute‑force the encryption of a PDF and read its confidential contents. This weakness, classified as CWE‑327, is rated medium severity by Chromium and can expose sensitive data to a malicious party with access to the victim’s browser.

Google Chrome builds that contain PDFium before version 147.0.7727.55 are affected. The vulnerability is specific to the built‑in PDF viewer; other browsers that do not use this PDFium version are not impacted.

The severity is moderate, with no publicly available EPSS score or KEV listing. Exploitation requires the attacker to supply a specially crafted encrypted PDF to the victim’s Chrome instance and perform a local brute‑force attempt, meaning that user interaction (opening the PDF) is necessary. Because the brute‑force can be automated, phishing or social‑engineering campaigns could disseminate dangerous PDFs widely, raising the risk to environments that rely on this browser component.