Race condition in a certain Red Hat patch to the PRNG lock implementation in the ssleay_rand_bytes function in OpenSSL, as distributed in openssl-1.0.1e-25.el7 in Red Hat Enterprise Linux (RHEL) 7 and other products, allows remote attackers to cause a denial of service (application crash) by establishing many TLS sessions to a multithreaded server, leading to use of a negative value for a certain length field.