CVE-2016-10158 in macOS
Summary
by MITRE
The exif_convert_any_to_int function in ext/exif/exif.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 (application crash) via crafted EXIF data that triggers an attempt to divide the minimum representable negative integer by -1.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2016-10158 represents a critical denial of service flaw within the PHP exif extension that affects multiple PHP versions including 5.6.x before 5.6.30, 7.0.x before 7.0.15, and 7.1.x before 7.1.1. This issue resides in the exif_convert_any_to_int function located in the ext/exif/exif.c source file, which processes EXIF metadata from image files. The flaw manifests when the function encounters crafted EXIF data that triggers a specific arithmetic operation involving the minimum representable negative integer value divided by negative one, creating a scenario that leads to application instability and potential system crashes.
The technical exploitation of this vulnerability stems from integer overflow and division by zero conditions within the exif processing code. When PHP attempts to parse EXIF data containing maliciously crafted values, the exif_convert_any_to_int function performs calculations that can result in attempting to divide the most negative integer value by negative one, which mathematically produces an overflow condition that crashes the PHP application process. This behavior aligns with CWE-369, which describes the improper handling of division by zero conditions, and specifically relates to CWE-191, which addresses integer underflow and overflow issues. The vulnerability demonstrates how seemingly benign metadata processing can become a vector for system disruption when proper input validation and error handling are absent.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides remote attackers with a reliable method to crash PHP applications that process EXIF data from untrusted sources. This includes web applications that accept image uploads, content management systems, photo sharing platforms, and any service that parses EXIF metadata without proper sanitization. Attackers can exploit this weakness by uploading or providing image files containing specially crafted EXIF data that triggers the division operation, resulting in application crashes that can lead to denial of service for legitimate users. The vulnerability is particularly concerning in web environments where PHP processes user-uploaded content, as it can be leveraged to continuously disrupt service availability without requiring authentication or elevated privileges. The ATT&CK framework categorizes this as a Denial of Service technique under the T1499 category, specifically involving network denial of service attacks through application-level vulnerabilities.
Mitigation strategies for CVE-2016-10158 primarily involve applying the official PHP security patches released by the PHP development team, which address the integer overflow condition in the exif_convert_any_to_int function. Organizations should prioritize updating their PHP installations to versions 5.6.30, 7.0.15, or 7.1.1 respectively, depending on their current PHP version. Additionally, implementing proper input validation and sanitization of EXIF data before processing can serve as an effective defensive measure, though this requires careful consideration of performance impacts. Network-level mitigations such as rate limiting and content filtering may help reduce the impact of exploitation attempts, while monitoring systems should be configured to detect unusual application crash patterns that might indicate exploitation attempts. Security teams should also consider implementing web application firewalls that can identify and block requests containing suspicious EXIF data patterns, providing an additional layer of protection against this specific vulnerability class.