CVE-2026-121131 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in Mobile in Google Chrome prior to 157.0.8103.38 allowed a remote attacker leveraging social engineering to execute arbitrary code outside the sandbox via a crafted Chrome extension. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as a use-after-free condition within Google Chrome prior to version 157.0.8103.38 represents a critical memory management flaw located in the mobile component of the browser engine. This specific defect arises when an object is deallocated from memory but remains accessible through dangling pointers, allowing subsequent operations to interact with freed or potentially reallocated memory regions. In the context of Chrome's architecture, such errors are particularly dangerous because they can bypass standard security boundaries if exploited correctly. The severity rating of High by the Chromium project underscores the potential for significant compromise, as use-after-free vulnerabilities are frequently leveraged in exploit chains to achieve arbitrary code execution with elevated privileges relative to the application sandbox.
The operational impact of this vulnerability is severe due to its remote nature and the specific attack vector involving crafted Chrome extensions. An attacker can distribute a malicious extension that contains carefully constructed JavaScript or native code designed to trigger the memory corruption flaw during normal browsing activities. By leveraging social engineering techniques, such as convincing users to install the extension under false pretenses of utility or security enhancement, the attacker gains a foothold within the browser environment. Once installed and activated, the crafted extension can manipulate internal data structures to exploit the use-after-free condition, potentially leading to arbitrary code execution outside the restrictive sandbox that normally isolates web content from the underlying operating system.
From a technical classification perspective, this vulnerability aligns with CWE-416, which defines Use After Free as an error where software uses memory after it has been freed. This misstep often leads to unpredictable behavior, including crashes or, more critically in security contexts, code execution. The attack methodology described corresponds closely to MITRE ATT&CK techniques related to Initial Access via Trusted Software Domains and Execution through Browser Extensions. Attackers utilize these trusted domains because extensions operate with higher privileges than standard web pages, providing a pathway to escape the sandboxed environment that protects user data and system integrity.
Mitigation strategies for this vulnerability primarily involve immediate software updates. Users of Google Chrome on mobile devices must upgrade to version 157.0.8103.38 or later, where the memory management logic has been corrected to prevent access to freed objects. Additionally, organizational security policies should enforce strict controls over extension installation, requiring administrative approval for any third-party add-ons and regularly auditing installed extensions for legitimacy. Security awareness training is also essential to mitigate the social engineering aspect of this threat, ensuring that users do not install unverified or suspicious browser modifications that could serve as vectors for such exploits.