PyCrypto before 2.6 does not produce appropriate prime numbers when using an ElGamal scheme to generate a key, which reduces the signature space or public key space and makes it easier for attackers to conduct brute force attacks to obtain the private key.
https://hermes.opensuse.org/messages/15083589
https://github.com/dlitz/pycrypto/blob/373ea760f21701b162e8c4912a66928ee30d401a/ChangeLog
https://exchange.xforce.ibmcloud.com/vulnerabilities/75871
https://bugs.launchpad.net/pycrypto/+bug/985164
http://www.securityfocus.com/bid/53687
http://www.openwall.com/lists/oss-security/2012/05/25/1
http://www.mandriva.com/security/advisories?name=MDVSA-2012:117
http://www.debian.org/security/2012/dsa-2502
http://secunia.com/advisories/49263
http://lists.fedoraproject.org/pipermail/package-announce/2012-June/081789.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-June/081759.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-June/081713.html