The X509Extension in pyOpenSSL before 0.13.1 does not properly handle a \0 character in a domain name in the Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.
It was discovered that pyOpenSSL incorrectly handled memory when handling X509 objects. A remote attacker could use this issue to cause pyOpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. This attack appears to be exploitable via Depends on the calling application and if it retains a reference to the memory. This vulnerability appears to have been fixed in 17.5.0.
It was discovered that pyOpenSSL incorrectly handled memory when performing operations on a PKCS #12 store. A remote attacker could possibly use this issue to cause pyOpenSSL to consume resources, resulting in a denial of service. This attack appear to be exploitable via Depends upon calling application, however it could be as simple as initiating a TLS connection that would cause the calling application to reload certificates from a PKCS …