CVE-2026-121241 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in Navigation in Google Chrome on on Android prior to 157.0.8103.38 allowed a remote attacker to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as a use-after-free error within the Navigation component of Google Chrome on Android prior to version 157.0.8103.38 represents a critical memory management flaw that undermines the browser's sandboxing mechanisms. This specific class of defect occurs when the application continues to reference a pointer after its associated memory has been deallocated or freed by another part of the system. In the context of web navigation, this typically involves lifecycle events where objects representing page states, frame trees, or resource loaders are destroyed while still being accessed by pending asynchronous operations or event handlers triggered by user interaction or automated scripts. The Chromium security team classified this issue with a High severity rating due to its potential for remote code execution and the complexity of exploitation mitigation within the browser architecture.
From a technical perspective, use-after-free vulnerabilities arise when an object is freed but remains accessible through dangling pointers. When Chrome processes navigation requests, it manages various internal structures that track loading states, security contexts, and resource allocation. If these structures are prematurely released while still referenced by active callbacks or background tasks, the memory previously occupied by those objects may be reallocated for unrelated purposes. An attacker controlling a crafted HTML page can manipulate timing conditions to trigger this race condition or state inconsistency. By carefully crafting JavaScript payloads that interact with navigation APIs and frame management features, an adversary can force the browser into a state where freed memory is interpreted as executable code or valid data structures. This misinterpretation allows for arbitrary read and write operations within the process space of the renderer.
The operational impact of this vulnerability is severe because it facilitates privilege escalation from the restricted sandboxed environment to the broader system context. Modern browsers rely on strict isolation between web content and host operating systems, ensuring that malicious scripts cannot directly access sensitive files or execute native code. However, a successful exploitation of this use-after-free flaw allows an attacker to bypass these protections. By achieving arbitrary memory write capabilities, the attacker can overwrite function pointers, return addresses, or other control flow data structures within the browser process. This leads to the execution of arbitrary shellcode with the privileges granted to the Chrome renderer process, which may have elevated permissions depending on the specific Android configuration and installed extensions. Consequently, this vulnerability enables remote code execution without any user interaction beyond visiting a malicious website, making it particularly dangerous in phishing campaigns or drive-by download attacks.
This incident aligns closely with Common Weakness Enumeration identifier CWE-416, which defines use-after-free as a critical memory safety error. Furthermore, the exploitation technique maps to MITRE ATT&CK techniques related to process injection and sandbox escape, specifically leveraging memory corruption to bypass security boundaries. The ability to execute code outside the sandbox is categorized under privilege escalation vectors where attackers transition from low-privilege web contexts to higher-privilege system levels. Defense-in-depth strategies are essential here since browser vulnerabilities often serve as initial access points for broader network compromises.
Mitigation requires immediate updates to Google Chrome on Android devices to version 157.0.8103.38 or later, where the underlying memory management logic in the Navigation component has been corrected to prevent dangling pointer dereferences. Developers and security teams should also enforce strict content security policies to limit script execution capabilities within web pages. Additionally, enabling sandboxing features such as site isolation ensures that even if a vulnerability is exploited, the blast radius remains contained within a single origin context rather than affecting the entire browser process or host system. Regular patch management cycles are critical for addressing these types of memory corruption vulnerabilities promptly before they can be weaponized in widespread attacks.