Two denial of service vulnerabilities were identified in strongSwan, an IKE/IPsec suite, using Google"s OSS-Fuzz fuzzing project. CVE-2017-9022 RSA public keys passed to the gmp plugin aren"t validated sufficiently before attempting signature verification, so that invalid input might lead to a floating point exception and crash of the process. A certificate with an appropriately prepared public key sent by a peer could be used for a denial-of-service attack. CVE-2017-9023 ASN.1 CHOICE types are not correctly handled by the ASN.1 parser when parsing X.509 certificates with extensions that use such types. This could lead to infinite looping of the thread parsing a specifically crafted certificate. A fix for a build failure was additionally included in the 5.2.1-6+deb8u4 revision of the strongSwan package.