Details ================ Software: Relevanssi Premium Version: v1.14.4 Homepage: https://www.relevanssi.com/ Advisory report: https://security.dxw.com/advisories/unserialization-vulnerability-in-relevanssi-premium-could-allow-admins-to-execute-arbitrary-code-in-some-circumstances/ CVE: Awaiting assignment CVSS: 9 (High; AV:N/AC:L/Au:S/C:C/I:C/A:C) Description ================ Unserialization vulnerability in Relevanssi Premium could allow admins to execute arbitrary code (in some circumstances) Vulnerability ================ If logged in as an admin on any site you can go to settings, Relevanssi Premium, import or export options. This is a text field that accepts a serialised PHPA object. It is possible to submit a string that contains an evil encoded object that executes arbitrary code (if there are classes available with particular methods such as __destruct). Proof of concept ================ AchievingA arbitrary code executionA depends onA which classes are available (i.e. which plugins and themes are installed and active). It wonat be possible in all situations. Mitigations ================ Upgrade to versionA 1.14.6.1 or later. Disclosure policy ================ dxw believes in responsible disclosure. Your attention is drawn to our disclosure policy: https://security.dxw.com/disclosure/ Please contact us on security@dxw.com to acknowledge this report if you received it via a third party (for example, plugins@wordpress.org) as they generally cannot communicate with us on your behalf. This vulnerability will be published if we do not receive a response to this report with 14 days. Timeline ================ 2016-10-07: Discovered 2016-11-01: Reported 2016-11-02:A Vendor reported fixed 2016-11-17: Requested CVE 2016-11-17:A Advisory published Discovered by dxw: ================ Glyn Wintle Please visit security.dxw.com for more information.