CVE-2014-1721 in Chrome
Summary
by MITRE
Google V8, as used in Google Chrome before 34.0.1847.116, does not properly implement lazy deoptimization, which allows remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via crafted JavaScript code, as demonstrated by improper handling of a heap allocation of a number outside the Small Integer (aka smi) range.
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Analysis
by VulDB Data Team • 05/10/2026
The vulnerability identified as CVE-2014-1721 affects Google V8 JavaScript engine implementation within Google Chrome browser versions prior to 34.0.1847.116. This issue stems from improper handling of lazy deoptimization mechanisms within the V8 engine's runtime execution environment. The vulnerability specifically manifests when the engine processes JavaScript code containing heap allocations that exceed the Small Integer (smi) range, creating a critical flaw in memory management and execution flow control. The V8 engine's lazy deoptimization feature is designed to optimize performance by initially compiling JavaScript code in a fast but less flexible mode, then deoptimizing to a more robust mode when necessary. However, in this case, the deoptimization process fails to properly handle certain edge cases involving numeric values that fall outside the smi range, leading to unpredictable behavior.
The technical exploitation of this vulnerability occurs through carefully crafted JavaScript code that triggers memory corruption during the lazy deoptimization process. When JavaScript code attempts to allocate numbers outside the smi range, the V8 engine's internal memory management system becomes inconsistent, potentially leading to memory corruption that can be leveraged for denial of service attacks. The smi range represents a specific integer value range that V8 optimizes for performance by storing values directly in pointers rather than as heap objects. When values exceed this range, they must be stored as heap objects, but the lazy deoptimization mechanism fails to properly transition between these memory representations, creating a memory corruption vulnerability. This flaw can potentially be exploited to execute arbitrary code or cause system instability, representing a significant security risk in web browser environments where untrusted JavaScript code is executed.
The operational impact of CVE-2014-1721 extends beyond simple denial of service scenarios, as the memory corruption vulnerabilities can potentially be leveraged for more sophisticated attacks. Attackers can craft malicious JavaScript payloads that, when executed in vulnerable Chrome versions, cause the browser to crash or behave unpredictably. The vulnerability's potential for unspecified other impacts suggests that it may provide a foothold for more advanced exploitation techniques, including privilege escalation or information disclosure. This type of vulnerability is particularly dangerous in the context of web browsers, where users frequently encounter untrusted content and where the attack surface is vast. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper memory management that can lead to arbitrary code execution. The ATT&CK framework would categorize this vulnerability under technique T1059.007 for JavaScript execution and T1499.004 for network denial of service, demonstrating how this vulnerability can be leveraged in multi-stage attack scenarios.
Mitigation strategies for CVE-2014-1721 primarily focus on updating to patched versions of Google Chrome, specifically version 34.0.1847.116 or later, which contain the necessary fixes for the lazy deoptimization implementation. Organizations should implement comprehensive patch management procedures to ensure all vulnerable systems are updated promptly. Additionally, browser hardening measures such as disabling unnecessary JavaScript features, implementing content security policies, and using sandboxing mechanisms can provide additional layers of protection. Security researchers and organizations should monitor for related vulnerabilities in the V8 engine and other JavaScript engines, as similar memory management issues may exist in other implementations. The vulnerability highlights the importance of proper memory management in high-performance JavaScript engines and underscores the need for rigorous testing of optimization features, particularly those involving lazy evaluation and deoptimization mechanisms. Regular security assessments of browser environments and implementation of web application firewalls can help detect and prevent exploitation attempts targeting this class of vulnerabilities.