The Memcache::getextendedstats function can be used to trigger an out-of-bounds read. Exploiting this issue requires control over memcached server hostnames and/or ports. This affects all supported versions of HHVM (3.30 and 3.27.4 and below).
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2018-6340.json"