CVE-2026-113300 in Chrome
Summary
by MITRE • 10/21/2026
Out of bounds write in Forms in Google Chrome prior to 156.0.8078.47 allowed a remote attacker to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 10/21/2026
The vulnerability identified as an out-of-bounds write within the Forms component of Google Chrome prior to version 156.0.8078.47 represents a critical memory safety flaw that undermines the browser's sandboxing mechanisms. This type of error occurs when a program writes data beyond the boundaries of a allocated buffer, potentially overwriting adjacent memory structures such as heap metadata or function pointers. In the context of web browsers like Chrome, which rely heavily on complex rendering engines and form handling subsystems to process user input and display dynamic content, improper bounds checking during the manipulation of HTML forms can lead to arbitrary memory corruption. The severity is classified as low by Chromium standards due to mitigations present in modern browser architectures, yet it remains a significant risk because out-of-bounds writes are frequently exploited as part of chain attacks to achieve code execution.
From a technical perspective, this flaw likely stems from insufficient validation checks when processing specific form elements or their associated attributes within the HTML parsing and rendering pipeline. When a crafted HTML page is loaded, the browser's engine may allocate memory buffers for storing form data or state information without correctly verifying that subsequent write operations remain within those allocated limits. An attacker can exploit this by constructing an HTML document containing specially designed input fields or scripts that trigger the malformed memory access pattern. The resulting out-of-bounds write allows the attacker to corrupt adjacent heap chunks, which is a prerequisite for gaining control over program execution flow. This aligns with Common Weakness Enumeration CWE-787, which defines out-of-bounds writes as writing data past the end or before the beginning of an allocated buffer, and CWE-120, which covers buffer copy without checking size limits.
The operational impact of this vulnerability is severe despite its low severity rating in internal tracking systems because it facilitates remote code execution outside the browser's sandbox environment. The Chrome sandbox isolates web content from the operating system to prevent malicious sites from accessing sensitive user data or installing malware. However, if an attacker successfully exploits a memory corruption flaw like this out-of-bounds write, they can bypass these isolation boundaries. This allows for arbitrary code execution with the privileges of the current user, potentially leading to full system compromise. According to the MITRE ATT&CK framework, this exploitation technique maps to T1203 Exploitation for Client Execution and specifically relates to techniques involving memory corruption such as heap spraying or use-after-free scenarios that often accompany out-of-bounds writes in complex software like browsers.
Mitigation strategies primarily involve updating Google Chrome to version 156.0.8078.47 or later, where the underlying code has been patched to include rigorous bounds checking and memory safety improvements within the Forms component. For organizations managing large fleets of devices, automated patch management systems should be configured to prioritize this update due to its potential for remote exploitation via standard web browsing activities. Additionally, users can reduce their exposure by employing browser hardening techniques such as disabling JavaScript on untrusted sites or using extensions that restrict form submission behaviors until the vulnerability is fully mitigated across all endpoints. Continuous monitoring of security advisories and maintaining up-to-date threat intelligence feeds are essential to stay ahead of potential exploit development efforts targeting this specific memory safety flaw.