Google Chrome EUVD-2026-34765

The victim must open or be made to render a maliciously crafted PDF file inside Google Chrome's built-in PDFium viewer (CVSS UI:R), so a single click on a link, an auto-loaded iframe pointing at a PDF, or an inline PDF preview suffices, but a fully headless drive-by without any user navigation does not. No authentication is required on the attacker side (PR:N) and the target Chrome instance must be running a version prior to 149.0.7827.53; exploitation is limited by Chrome's renderer sandbox, meaning a second sandbox-escape vulnerability is realistically needed to reach the host OS, and by the fact that disabling the internal PDF viewer (AlwaysOpenPdfExternally policy) entirely removes the attack surface.

The signals here are notably divergent and should temper urgency: CVSS 3.1 vector AV:N/AC:L/PR:N/UI:R rates this 8.8 (High) based on network reach, low complexity, no privileges, and user interaction, but Google's own Chromium severity is Low, EPSS sits at 0.03% (11th percentile - essentially no predicted exploitation), and CISA SSVC reports Exploitation: none and Automatable: no while still flagging Technical Impact: total. The CVSS score reflects worst-case impact assuming a renderer compromise leads to code execution, whereas the Chromium 'Low' rating likely accounts for the sandbox containment and difficulty of weaponizing this specific UAF. There is no public exploit identified at time of analysis and no CISA KEV listing, so this is best treated as a routine Chrome stable-channel patch rather than an emergency; the priority is normal browser update hygiene, not out-of-band response.

An attacker hosts a malicious PDF on a webpage or sends it as an email attachment that opens in the browser; when the victim navigates to the page or clicks the file, Chrome's PDFium parser triggers the use-after-free, corrupting heap memory in the renderer process. Successful exploitation would give the attacker code execution confined to the sandboxed renderer, requiring a chained sandbox escape to compromise the host - no public PoC is identified at time of analysis.