CVE-2026-17749 in Chrome
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in Extensions in Google Chrome prior to 151.0.7922.72 allowed an attacker who convinced a user to install a malicious extension to potentially perform a sandbox escape via a crafted Chrome Extension. (Chromium security severity: Medium)
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical sandbox escape opportunity within the Chrome browser's extension architecture that existed prior to version 151.0.7922.72. The flaw stems from inadequate input validation mechanisms within the extension installation and execution pipeline, specifically targeting the handling of untrusted data provided by malicious extensions. The vulnerability manifests when a user installs a crafted malicious extension, which can then exploit insufficient validation controls to break out of the restricted browser sandbox environment that normally isolates extension processes from the underlying system. This represents a classic sandbox escape vector that aligns with common attack patterns documented in the ATT&CK framework under technique T1059 for executing code within compromised environments. The vulnerability's classification as Medium severity by Chromium security team reflects its potential impact on user system integrity, though it requires user interaction to exploit. The root cause can be mapped to CWE-20, which describes inadequate input validation, specifically in contexts where untrusted data flows through extension installation processes without proper sanitization or verification mechanisms.
The technical exploitation of this vulnerability relies on the attacker's ability to craft a malicious Chrome extension that appears legitimate to users while containing code designed to bypass Chrome's security boundaries. Extensions in Chrome operate within a restricted sandboxed environment to prevent them from accessing sensitive system resources directly, but insufficient validation allows crafted inputs to potentially manipulate extension behavior or execution context. The vulnerability typically occurs during the extension installation process where metadata, manifest files, or other extension components are processed without adequate verification of their integrity or authenticity. Attackers can leverage this weakness by creating extensions that exploit legitimate browser APIs or by crafting payloads that can execute in contexts where normal sandbox restrictions do not apply. This type of attack follows common exploitation patterns documented in various security frameworks and represents a significant threat to user privacy and system security.
The operational impact of this vulnerability extends beyond simple privilege escalation, as successful exploitation could enable attackers to access user data, monitor browser activities, install additional malicious software, or perform other harmful actions within the compromised browser environment. Users who install malicious extensions may unknowingly expose their systems to persistent threats that can operate undetected for extended periods. The attack vector requires social engineering to convince users to install the malicious extension, making it particularly dangerous in environments where users may not be security-aware. The vulnerability affects Chrome's extension security model and undermines the fundamental principle of sandbox isolation that protects users from potentially harmful browser extensions. Organizations using Chrome-based browsers face increased risk of data breaches or persistent threats when users encounter and install malicious extensions through legitimate channels.
Mitigation strategies for this vulnerability primarily involve updating to Chrome version 151.0.7922.72 or later, where the input validation issues have been addressed through enhanced extension processing mechanisms. Browser administrators should implement strict extension management policies that limit extension installation to trusted sources and maintain regular update schedules to ensure all security patches are applied promptly. Organizations can also employ browser hardening techniques such as disabling unnecessary extension APIs, implementing content security policies, and monitoring for unusual extension behavior or unauthorized installations. Additional defensive measures include user education about the risks of installing extensions from untrusted sources, implementation of extension whitelisting policies, and regular security audits of installed extensions to identify potential threats. The vulnerability highlights the importance of maintaining up-to-date browser software and implementing layered security controls to protect against sophisticated attacks that exploit browser security boundaries through carefully crafted malicious content.