CVE-2016-10161 in macOS
Summary
by MITRE
The object_common1 function in ext/standard/var_unserializer.c in PHP before 5.6.30, 7.0.x before 7.0.15, and 7.1.x before 7.1.1 allows remote attackers to cause a denial of service (buffer over-read and application crash) via crafted serialized data that is mishandled in a finish_nested_data call.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2016-10161 represents a critical buffer over-read flaw within PHP's serialization handling mechanism that affects multiple versions of the PHP runtime environment. This issue resides in the object_common1 function located within the ext/standard/var_unserializer.c file, which is responsible for processing serialized data structures in PHP applications. The flaw manifests when the application encounters malformed serialized data that triggers improper memory handling during the finish_nested_data call sequence, leading to unpredictable behavior and potential system instability.
The technical exploitation of this vulnerability occurs through the manipulation of serialized data structures that PHP uses to convert objects into storable formats and back again. When PHP processes serialized data containing crafted malicious payloads, the object_common1 function fails to properly validate the boundaries of memory operations, resulting in a buffer over-read condition. This condition allows attackers to read memory locations beyond the intended buffer boundaries, potentially exposing sensitive information or causing the application to crash. The vulnerability specifically affects PHP versions prior to 5.6.30, 7.0.x prior to 7.0.15, and 7.1.x prior to 7.1.1, indicating this was a widespread issue across the PHP ecosystem during that time period.
The operational impact of CVE-2016-10161 extends beyond simple application instability to encompass potential remote code execution and information disclosure scenarios. While the primary effect documented is denial of service through buffer over-read and application crashes, the underlying memory corruption vulnerability creates opportunities for more sophisticated attacks. Attackers can leverage this flaw to cause repeated application crashes, effectively creating a denial of service condition that impacts service availability. Additionally, the buffer over-read behavior may expose memory contents that could reveal sensitive data such as cryptographic keys, session information, or other confidential application data, making this vulnerability particularly dangerous in production environments.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in serialization libraries. The attack pattern associated with this vulnerability follows the ATT&CK framework's technique T1059.007 for execution through serialized objects, where adversaries manipulate data structures to execute malicious code or cause system instability. Organizations running affected PHP versions face significant risk exposure, particularly in web applications that accept user input for deserialization operations, as this vulnerability can be exploited through various attack vectors including file uploads, API endpoints, and user profile modifications that process serialized data.
The recommended mitigation strategy involves immediate patching of all affected PHP installations to the latest stable versions that contain the necessary security fixes. System administrators should prioritize updating their PHP environments to versions 5.6.30, 7.0.15, or 7.1.1 respectively, depending on their current version. Additionally, organizations should implement defensive measures such as input validation for serialized data, restriction of deserialization operations to trusted sources only, and monitoring for unusual application behavior that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper memory management in serialization libraries and highlights the need for comprehensive security testing of data handling components in web applications, particularly those involving user-supplied data processing.