CVE-2026-106255 in Chrome
Summary
by MITRE • 10/06/2026
Race condition in V8 in Google Chrome prior to 155.0.8059.39 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 • 10/07/2026
The vulnerability identified as a race condition within the V8 JavaScript engine, which powers Google Chrome prior to version 155.0.8059.39, represents a critical flaw in how concurrent operations are managed during memory allocation and type checking processes. Race conditions typically arise when software performs two or more operations that must occur sequentially but instead execute concurrently due to insufficient synchronization mechanisms. In the context of V8, this likely involves scenarios where an object's state is modified by one thread while another thread attempts to access or manipulate it based on stale assumptions about its type or memory layout. This lack of atomicity allows a remote attacker who crafts a malicious HTML page containing specific JavaScript code to exploit the timing window between these operations. By carefully controlling execution speed and triggering specific garbage collection cycles or JIT compilation steps, an attacker can force V8 into an inconsistent state where it misinterprets data types or memory boundaries.
From a technical perspective, this flaw falls under CWE-362, which defines concurrent execution using shared resources with improper synchronization. The exploitation of such vulnerabilities often leads to type confusion attacks, where the engine incorrectly assumes one data type for a value that is actually another, leading to out-of-bounds reads or writes when operations are performed on the misidentified object. This mechanism aligns closely with ATT&CK technique T1059.007, which covers JavaScript execution within browser environments. The attacker leverages this race condition to bypass V8's type safety checks and sandbox restrictions, effectively achieving arbitrary code execution inside the browser process. Although Chrome employs multiple layers of defense such as site isolation and memory protection features like ASLR and DEP, a successful exploitation of this high-severity flaw can allow an adversary to escape these protections or at least execute malicious payloads within the restricted context of the renderer process, potentially leading to further privilege escalation if other vulnerabilities are chained.
The operational impact of this vulnerability is significant because it enables remote code execution through simple web browsing actions. A user visiting a compromised website or clicking on a specially crafted link can trigger the race condition without any additional interaction required from them. This lowers the barrier for entry significantly compared to exploits requiring complex user interactions like file uploads or plugin installations. The severity rating of High by Chromium security reflects the potential for widespread impact, as it affects all users running versions prior to the patch release. Attackers could use this capability to install malware, steal sensitive data such as cookies and session tokens stored in browser memory, or establish persistent access if combined with other vulnerabilities that allow escaping the sandbox entirely.
Mitigation strategies primarily involve immediate software updates. Administrators and end-users must upgrade Google Chrome to version 155.0.8059.39 or later, where the race condition has been addressed by implementing proper synchronization primitives such as locks or atomic operations within V8's internal handling of shared objects during concurrent execution paths. Until patches are applied, organizations should consider deploying browser isolation technologies like Microsoft Edge IE Mode or third-party sandboxing solutions to limit the impact if a user inadvertently visits malicious content. Additionally, enabling Chrome’s built-in security features, such as Site Isolation and Safe Browsing protections, can help mitigate some downstream effects by restricting cross-origin data access and blocking known malicious URLs, although these measures do not prevent the initial exploitation of the race condition itself. Regular monitoring for unusual browser behavior or memory anomalies may also aid in detecting attempted exploits in real-time environments where patching is delayed.