CVE-2026-17987
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in Notifications in Google Chrome prior to 151.0.7922.72 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted PDF file. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical sandbox escape vector that emerged from insufficient input validation within Chrome's notification handling mechanism. The flaw existed in Google Chrome versions prior to 151.0.7922.72 and specifically targeted the renderer process compromise scenario where an attacker had already gained execution privileges within the browser's sandboxed environment. The vulnerability stems from inadequate sanitization of untrusted input when processing notifications triggered by malicious PDF files, creating a pathway for privilege escalation that bypasses Chrome's core security boundaries.
The technical implementation of this vulnerability involves the manipulation of notification parameters through crafted PDF content that triggers improper input validation in Chrome's rendering pipeline. When a compromised renderer process encounters a maliciously constructed PDF file, the notification system fails to properly validate or sanitize the embedded data before processing it within the browser's broader execution context. This validation gap allows attackers to inject malicious payloads that can exploit the notification subsystem to break out of the restricted renderer sandbox and gain elevated privileges within the browser's more privileged processes.
From an operational standpoint, this vulnerability significantly impacts Chrome's security model by undermining the fundamental principle of process isolation that separates renderer processes from browser processes. The attack vector requires initial compromise of the renderer process, which aligns with the concept of privilege escalation in the attack chain. According to the attack tactics framework, this represents a sandbox escape technique that leverages weaknesses in input validation to achieve higher privilege execution levels. The low severity classification from Chromium's security team belies the actual impact, as sandbox escapes typically represent high-value targets for attackers seeking persistent access and system compromise.
The vulnerability maps directly to CWE-20, which describes improper input validation in software systems, and aligns with attack patterns documented in the MITRE ATT&CK framework under privilege escalation techniques. Organizations using affected Chrome versions face significant risk exposure when users encounter malicious PDF content, as this vulnerability can be exploited without user interaction once the renderer process has been compromised through other means such as drive-by downloads or social engineering attacks. The attack chain typically begins with initial exploitation of a renderer vulnerability, followed by leveraging this notification validation flaw to achieve system-level compromise.
Mitigation strategies should focus on immediate patching of Chrome installations to version 151.0.7922.72 or later, which implements proper input validation for notification parameters. Network administrators should also consider implementing additional security controls such as PDF content filtering and sandbox hardening measures. The broader security community should monitor for similar vulnerabilities in other browser components that may exhibit similar patterns of insufficient input validation, particularly in areas where user-provided content is processed through notification or alert systems. Organizations should conduct thorough vulnerability assessments to identify any potential exploitation attempts that may have occurred prior to patch deployment, as this type of sandbox escape vulnerability can provide attackers with persistent access to compromised systems.