CVE-2016-1688 in Chrome
Summary
by MITRE
The regexp (aka regular expression) implementation in Google V8 before 5.0.71.40, as used in Google Chrome before 51.0.2704.63, mishandles external string sizes, which allows remote attackers to cause a denial of service (out-of-bounds read) via crafted JavaScript code.
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability identified as CVE-2016-1688 represents a critical flaw in the Google V8 JavaScript engine's regular expression implementation that affected Google Chrome versions prior to 51.0.2704.63. This issue stems from improper handling of external string sizes within the V8 engine's regex processing subsystem, creating a significant security risk that could be exploited remotely. The vulnerability specifically manifests when the engine encounters crafted JavaScript code containing malicious regular expressions that manipulate external string boundaries in unexpected ways.
The technical flaw occurs within the V8 engine's internal string handling mechanisms where external strings are processed during regular expression operations. When the regex engine encounters malformed or specially crafted string inputs, it fails to properly validate the boundaries of external string representations, leading to out-of-bounds memory reads. This memory access violation occurs because the engine does not adequately check the actual size of external string buffers before attempting to access memory locations beyond the allocated boundaries. The vulnerability is classified as a buffer over-read condition that can be triggered through carefully constructed JavaScript regular expression patterns, making it particularly dangerous in web browser environments where arbitrary JavaScript execution is possible.
The operational impact of this vulnerability extends beyond simple denial of service, as it creates potential pathways for more sophisticated attacks within the browser environment. Remote attackers can leverage this flaw to cause unpredictable behavior in the Chrome browser, potentially leading to system instability or crashes that could be exploited for further attacks. The out-of-bounds read condition could theoretically be chained with other vulnerabilities to achieve arbitrary code execution, though direct exploitation typically requires additional attack vectors. This vulnerability affects the core JavaScript engine functionality and impacts all web applications running in affected Chrome versions, making it particularly concerning for enterprise environments where browser-based attacks are common.
Mitigation strategies for CVE-2016-1688 primarily focus on immediate software updates and browser version management. Organizations should prioritize updating to Chrome version 51.0.2704.63 or later, which contains the necessary patches to address the external string size handling issue. Additionally, implementing network-level protections such as web application firewalls and content security policies can help reduce the attack surface by limiting the execution of potentially malicious JavaScript code. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and may relate to ATT&CK techniques involving code injection and privilege escalation through browser-based exploits. Security teams should also consider implementing browser hardening measures and monitoring for suspicious JavaScript behavior patterns that might indicate exploitation attempts.