CVE-2026-17990 in Chrome
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in WebAuthn 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
The vulnerability under discussion represents a critical sandbox escape opportunity within Google Chrome's WebAuthn implementation, specifically affecting versions prior to 151.0.7922.72. This flaw stems from insufficient validation of untrusted input within the WebAuthn framework, which is designed to provide secure authentication mechanisms using public key cryptography. The vulnerability manifests when an attacker compromises the renderer process and leverages a crafted PDF file to exploit the inadequate input validation, potentially bypassing Chrome's security boundaries.
WebAuthn is a web standard that enables secure authentication through public key cryptography, allowing users to authenticate using devices such as USB security keys, biometric readers, or built-in platform authenticators. The implementation in Chrome includes multiple security layers including sandboxing to isolate renderer processes from the main browser and underlying operating system. When input validation fails within this framework, it creates an attack vector that can be exploited by malicious actors who have already gained access to the renderer process, which typically operates with reduced privileges but still maintains access to browser functionality.
The technical flaw involves a failure in the validation mechanisms that process untrusted data from PDF files when they interact with WebAuthn APIs. This represents a classic sandbox escape vulnerability where an attacker can use legitimate browser functionality to break out of restricted execution environments. The Chromium security severity rating of Low suggests that while the impact is significant, it requires specific preconditions including prior compromise of the renderer process. However, this classification may understate the risk given that WebAuthn authentication is a critical security component in many applications and services.
This vulnerability has implications for several cybersecurity frameworks and attack patterns. From a CWE perspective, this corresponds to weakness categories such as CWE-20 (Improper Input Validation) and potentially CWE-787 (Out-of-bounds Write), depending on the specific implementation details of how the validation failure manifests. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under T1059 (Command and Scripting Interpreter) and T1078 (Valid Accounts) where an attacker who already has access to a compromised renderer process can escalate privileges or bypass security controls.
The operational impact of this vulnerability extends beyond simple privilege escalation, potentially allowing attackers to access sensitive authentication data or impersonate users in systems that rely on WebAuthn for authentication. This is particularly concerning given that many organizations use WebAuthn as part of their multi-factor authentication strategies, making the potential compromise of this mechanism especially damaging to overall security posture. The vulnerability also affects the trust model of browser-based authentication systems, potentially undermining user confidence in secure authentication mechanisms.
Mitigation strategies should focus on immediate remediation through Chrome updates to version 151.0.7922.72 or later, while organizations should implement additional monitoring for suspicious PDF file handling and WebAuthn API usage patterns. The vulnerability highlights the importance of comprehensive input validation across all browser components and demonstrates how seemingly isolated security mechanisms can create attack vectors when integrated with other browser functionalities. Security teams should also consider implementing network-based detection measures that monitor for unusual authentication patterns or attempts to access WebAuthn functionality from compromised processes, particularly in environments where WebAuthn is heavily utilized for critical system access.