A flaw was found in openCryptoki. The openCryptoki Soft token does not check if an EC key is valid when an EC key is created via CCreateObject, nor when CDeriveKey is used with ECDH public data. This may allow a malicious user to extract the private key by performing an invalid curve attack.

opencryptoki, when compiled with -DSPINXPL (as it is in Red Hat Enterprise Linux and Fedora), creates certain dot files in the /tmp directory, such as .pkapixpk and .pkcs11spinloc. These are not temporary files and are rather used for locking purposes. They are created in a way that allows symlink attacks.

As files are opened RDWR, and not written to, they don't seem to allow file corruption as typical symlink attacks do. It is still possible to create new files at arbitrary locations (e.g. /etc/nologin) or make arbitrary file world writable (e.g. /etc/shadow) with the privileges of the user running pkcsslotd or an application using opencrpytoki library. Attacker does not need to be a member of the pkcs11 group, though symlinks would usually need to be created before the first use of the opencryptoki on the system.