CVE-2026-118304 in Chrome
Summary
by MITRE • 10/28/2026
Improper input validation in SVG in Google Chrome prior to 156.0.8078.73 allowed a remote attacker to potentially execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability described involves an improper input validation flaw within the SVG rendering engine of Google Chrome prior to version 156.0.8078.73. This defect allows a remote attacker to potentially execute arbitrary code inside the browser's sandbox by crafting a malicious HTML page that contains specially constructed Scalable Vector Graphics elements. The core technical issue stems from insufficient checks on input data processed during the parsing and rendering of SVG content, which is commonly embedded in web pages for graphical representation. When Chrome processes these malformed or crafted SVG structures, it fails to properly validate certain attributes or properties before passing them to lower-level system components responsible for graphics processing. This lack of rigorous validation creates a pathway for memory corruption or logic errors that can be exploited to break out of the restrictive sandbox environment designed to isolate web content from the host operating system.
From a technical perspective, this type of vulnerability is typically classified under CWE-20 Improper Input Validation and often leads to outcomes categorized as CWE-787 Out-of-bounds Write or CWE-119 Memory Corruption based on the specific nature of the exploit code. The attacker crafts an HTML page that embeds SVG elements with malformed data structures, such as incorrect array indices, invalid object references, or improperly formatted numeric values. When the browser's rendering engine attempts to process these inputs without adequate boundary checks or type verification, it may write data to unintended memory locations or execute arbitrary instructions within the context of the Chrome sandboxed process. Although the sandbox provides a layer of defense by limiting permissions and isolating processes, sophisticated exploits can leverage this input validation failure to achieve code execution with elevated privileges relative to other web content, potentially leading to full system compromise if further exploitation steps are successful.
The operational impact of this vulnerability is significant due to its remote nature and high severity rating assigned by the Chromium security team. A user visiting a malicious website containing the crafted HTML page could trigger the exploit without any additional interaction beyond loading the page, depending on how the SVG content is triggered. This aligns with ATT&CK technique T1059 Command and Scripting Interpreter if script-based vectors are used within the SVG, or more critically, techniques related to sandbox escape such as those involving process injection or memory manipulation. The ability to execute arbitrary code inside the sandbox undermines the fundamental security model of modern web browsers, which relies on strict isolation between tabs and processes. Successful exploitation could allow an attacker to install malware, steal sensitive data stored in cookies or local storage, perform keylogging, or use the compromised browser as a pivot point for further network attacks against internal systems if the user is connected to corporate networks.
Mitigation strategies primarily involve updating Google Chrome to version 156.0.8078.73 or later, where these input validation checks have been strengthened and patched by the Chromium development team. Organizations should enforce automatic update policies for browsers across all endpoints to ensure that security patches are applied promptly upon release. Additionally, users can employ browser hardening techniques such as disabling JavaScript execution on untrusted sites using extensions like NoScript or configuring strict Content Security Policies if they control the web applications being accessed. Network-level defenses including next-generation firewalls and intrusion prevention systems may also detect and block traffic associated with known exploit kits distributing this specific malicious HTML payload, although direct exploitation via a crafted link remains difficult to mitigate without patching the underlying browser vulnerability. Regular security awareness training for users regarding suspicious links and websites serves as an additional layer of defense against social engineering tactics often used in conjunction with such technical exploits.