HIGH
PHP through 5.6.27 and 7.x through 7.0.12 mishandles property modification during __wakeup processing, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via crafted serialized data, as demonstrated by Exception::__toString with DateInterval::__wakeup.
http://www.openwall.com/lists/oss-security/2016/11/01/2
Source: MITRE
Published: 2017-01-04
Updated: 2017-01-07
Type: CWE-416
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL