CVE-2026-121246 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in WebGL 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: Critical)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability described constitutes a critical use-after-free flaw within the WebGL implementation of Google Chrome on Android, specifically affecting versions prior to 157.0.8103.38. This type of memory corruption error arises when software continues to use a pointer after it has been freed from dynamic memory allocation. In the context of browser-based rendering engines like Chromium's GPU process and WebGL subsystems, such errors are particularly dangerous because they can lead to arbitrary code execution with high privileges relative to the sandboxed environment. The severity is classified as critical by the Chromium security team due to the potential for remote attackers to bypass standard browser isolation mechanisms through a crafted HTML page delivered via a website or email attachment.
From a technical perspective, WebGL relies heavily on efficient memory management to handle complex graphical operations and shader programs. When an object representing GPU resources or JavaScript bindings is deallocated but remains referenced by other parts of the application state, accessing that freed memory can result in undefined behavior. An attacker exploiting this flaw could manipulate heap metadata or overwrite adjacent objects with controlled data structures. This manipulation allows for precise control over program execution flow, potentially leading to arbitrary code execution within the browser process context. The attack vector is remote and requires user interaction only in the sense of visiting a maliciously crafted webpage that triggers the specific sequence of WebGL operations leading to the use-after-free condition.
The operational impact of this vulnerability extends beyond simple data exposure or denial of service. Successful exploitation enables an attacker to execute arbitrary code outside the browser's sandbox, effectively compromising the integrity and confidentiality of the user system. This could lead to full device compromise on Android devices running affected versions, allowing for installation of malware, exfiltration of sensitive personal information, or use of the device as part of a botnet. The ability to escape the sandbox is particularly significant because modern browsers rely heavily on sandboxes to limit the damage caused by web-based attacks. Bypassing these protections removes a primary defense layer against drive-by download attacks and other remote exploitation techniques.
Industry standards classify this vulnerability under CWE-416, which defines use after free as a condition where software uses memory that has already been freed. This category of flaws is consistently among the most prevalent in complex C++ codebases like Chromium due to manual memory management requirements. Furthermore, from an offensive security perspective aligned with MITRE ATT&CK frameworks, this vulnerability facilitates techniques related to initial access and privilege escalation within the host environment. Attackers often leverage such vulnerabilities during targeted campaigns or automated scanning efforts to gain a foothold on vulnerable systems before deploying more specialized payloads for lateral movement or persistence.
Mitigation strategies primarily involve immediate software updates. Users of Google Chrome on Android must update their browsers to version 157.0.8103.38 or later, where the memory management logic in WebGL has been corrected to ensure proper reference counting and nullification of pointers after deallocation. For organizations managing fleets of devices, enforcing automatic browser updates is crucial to minimize exposure windows. Additionally, security awareness training can help users recognize suspicious links that might lead to pages containing exploit code targeting this specific vulnerability. While no perfect technical workaround exists for end-users other than patching, deploying web application firewalls or intrusion detection systems capable of identifying known exploitation patterns related to WebGL memory corruption may provide an additional layer of defense against active threats in the wild.