CVE-2026-118307 in Chrome
Summary
by MITRE • 10/28/2026
Use after free in Paint 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 identified as a use-after-free flaw within the Paint component of Google Chrome prior to version 156.0.8078.73 represents a critical memory management error that compromises the integrity of the browser's execution environment. This specific class of defect occurs when the application continues to reference a block of memory after it has been freed, leading to undefined behavior during runtime operations. In the context of web browsers, such flaws are particularly dangerous because they can be triggered by maliciously crafted content served from remote servers, allowing an attacker to manipulate how the browser handles graphical rendering data without requiring any user interaction beyond visiting a compromised webpage.
From a technical perspective, this vulnerability falls under the Common Weakness Enumeration category CWE-416, which defines use-after-free errors as conditions where pointers are used after they have been freed or deallocated. The Paint component is responsible for handling various graphical operations and rendering tasks within the Chromium engine. When an attacker crafts an HTML page that triggers a specific sequence of events involving object lifecycle management, it can cause the system to release memory associated with certain paint objects while retaining references to them elsewhere in the codebase. Subsequent access to these dangling pointers allows the attacker to write arbitrary data into previously freed memory regions or read sensitive information from those locations.
The operational impact of this vulnerability is severe due to its potential for remote code execution within the browser's sandboxed environment. Although modern browsers employ multiple layers of defense such as site isolation and hardware-based protections, a successful exploitation of a use-after-free condition can often bypass these safeguards by achieving arbitrary read/write primitives. This capability enables an attacker to execute arbitrary commands on the victim's machine with the privileges granted to the browser process. The Chromium security team has classified this issue with high severity because it directly impacts the core security model that protects users from malicious web content, potentially leading to full system compromise if other mitigations fail.
This type of exploitation aligns closely with tactics observed in advanced persistent threats and is categorized under MITRE ATT&CK technique T1203, which covers Exploitation for Client Execution. Attackers typically leverage such vulnerabilities by embedding the exploit code within a seemingly benign webpage or through drive-by download mechanisms that automatically trigger when a user visits the site. The lack of required user interaction beyond page load makes this vector highly effective for mass exploitation campaigns targeting unpatched installations of Chrome.
To mitigate the risks associated with this vulnerability, organizations and individual users must ensure that Google Chrome is updated to version 156.0.8078.73 or later immediately upon availability. Regular patch management cycles are essential to address such high-severity flaws before they can be widely exploited in the wild. Additionally, deploying browser isolation technologies or sandboxing solutions can provide an additional layer of defense by limiting the potential impact if a vulnerability is successfully triggered. Security teams should also monitor for indicators of compromise related to unusual memory usage patterns or unexpected network connections originating from browser processes, which may signal active exploitation attempts against unpatched systems.