CVE-2026-121100 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in DOM in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to execute arbitrary code inside 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 described constitutes a critical use-after-free flaw within the Document Object Model implementation of Google Chrome prior to version 157.0.8103.38. This type of memory corruption error occurs when a program continues to use a pointer after it has been freed, leading to undefined behavior that can be exploited by malicious actors. In this specific instance, the flaw resides in how Chromium manages DOM nodes and their associated memory allocations during rendering or manipulation processes. When an attacker crafts a specially designed HTML page containing JavaScript code that triggers premature deallocation of a DOM object while references to it are still active within the browser engine, the application may access invalid memory addresses. This scenario creates a window for arbitrary code execution because the freed memory might be reallocated for other purposes, allowing the attacker to control the data stored in that region and subsequently hijack program flow through techniques such as function pointer overwrites or vtable manipulation.
From an operational perspective, this vulnerability poses a severe risk due to its potential for remote exploitation via standard web browsing activities. A victim merely needs to visit a malicious website hosting the crafted HTML page for the exploit chain to initiate. The severity is classified as high by Chromium security standards because it bypasses several layers of browser isolation and sandboxing mechanisms designed to contain damage from compromised websites. If successful, an attacker could execute arbitrary code with the privileges of the user running the browser, potentially leading to full system compromise depending on the context in which the browser operates. This includes access to sensitive data stored locally, such as cookies, passwords, and session tokens, as well as the ability to install persistent malware or pivot into internal network resources if the victim is part of a corporate environment with less restrictive browsing policies.
The technical classification of this flaw aligns closely with Common Weakness Enumeration identifier CWE-416, which defines use-after-free errors resulting from improper memory management practices. In the context of modern web browsers, these vulnerabilities are particularly dangerous because they often serve as the initial vector for more complex attack chains that aim to escape the browser sandbox. The exploitation typically involves a series of steps including heap grooming to control memory layout, triggering the free operation through DOM manipulation, and then accessing the freed memory via remaining references to overwrite critical data structures. This process allows the attacker to gain code execution capabilities within the renderer process before attempting further escalation techniques to break out into the host operating system.
Mitigation strategies for this vulnerability primarily involve immediate software updates. Users must upgrade Google Chrome to version 157.0.8103.38 or later, where the underlying memory management logic has been patched to ensure that references are properly invalidated upon deallocation and that access checks prevent interaction with freed memory regions. For organizations managing large fleets of devices, deploying automated patching solutions is essential to reduce exposure time. Additionally, implementing strict content security policies can help mitigate some risks by restricting inline scripts or untrusted sources, although such measures do not fully protect against zero-day vulnerabilities in the browser engine itself. Security teams should also monitor for indicators of compromise related to this specific CVE and ensure that endpoint detection systems are updated to recognize exploitation attempts targeting Chrome memory corruption flaws.
In terms of threat intelligence frameworks, this vulnerability maps to MITRE ATT&CK technique T1203, which covers exploitation for client execution. The attack vector is classified as remote via network (T1190), and the impact includes unauthorized access to information (TA0006) and potential privilege escalation if sandbox escape techniques are successfully combined with this initial foothold. Understanding these mappings helps security operations centers prioritize response efforts based on the likelihood of exploitation in the wild and the criticality of affected assets. Continuous monitoring for similar memory corruption issues across all web browsers is recommended, as attackers frequently target browser engines due to their widespread use and complex codebases that may contain subtle logic errors exploitable through crafted media or markup content.