Known security limitations
Lack of secure memory wiping
Memory wiping is used to protect secret data or key material from attackers with access to uninitialized memory. This can be either because the attacker has some kind of local user access or because of how other software uses uninitialized memory.
Python exposes no API for us to implement this reliably and as such almost all software in Python is potentially vulnerable to this attack. The CERT secure coding guidelines assesses this issue as "Severity: medium, Likelihood: unlikely, Remediation Cost: expensive to repair" and we do not consider this a high risk for most users.