A flaw was found in strongSwan 4.x and 5.x before 5.7.0. In verify_emsa_pkcs1_signature() in gmp_rsa_public_key.c in the gmp plugin, the RSA implementation based on GMP does not reject excess data after the encoded algorithm OID during PKCS#1 v1.5 signature verification. Similar to the flaw in the same version of strongSwan regarding digestAlgorithm.parameters, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation when only an RSA signature is used for IKEv2 authentication. References: https://www.strongswan.org/blog/2018/09/24/strongswan-vulnerability-(cve-2018-16151,-cve-2018-16152).html
Created strongswan tracking bugs for this issue: Affects: epel-all [bug 1635874] Affects: fedora-all [bug 1635875]
Strongswan in Red Hat Enterprise Linux does not enable the gmp plugin. Therefore this flaw does not affect Red Hat Enterprise Linux 7 build of strongswan.