diff --git a/src/libstrongswan/plugins/x509/x509_cert.c b/src/libstrongswan/plugins/x509/x509_cert.c
index b3d90c5f6..7068853a8 100644
--- a/src/libstrongswan/plugins/x509/x509_cert.c
+++ b/src/libstrongswan/plugins/x509/x509_cert.c
@@ -1461,6 +1461,7 @@ static bool parse_certificate(private_x509_cert_t *this)
 						}
 						break;
 					case OID_AUTHORITY_KEY_ID:
+						chunk_free(&this->authKeyIdentifier);
 						this->authKeyIdentifier = x509_parse_authorityKeyIdentifier(
 									object, level, &this->authKeySerialNumber);
 						break;