Multiple serious vulnerabilities have been found in PHP through 5.6.27 and 7.x through 7.0.12. Malicious users can exploit these vulnerabilities to cause a denial of service. Other unspecified impacts are also possible.

Below is a complete list of vulnerabilities:

1. Mishandling of property modification during __wakeup processing can be exploited remotely via specially designed serialized data to cause a denial of service;
2. Use-after-free vulnerability in the CURLFile implementation (ext/curl/curl_file.c) can be exploited remotely via specially designed data mishandled while __wakeup processing to cause a denial of service.

PHP through 5.6.27
PHP 7.x through 7.0.12

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PHP 5 ChangeLog
PHP 7 ChangeLog