Executive brief
A Perl library used for secure password hashing and data encryption contains a flaw in how it generates random numbers. If certain security modules are missing from the system, the library uses a predictable method to generate keys, which could allow an attacker to more easily guess passwords or decrypt protected data. This impacts the overall strength of the security measures protecting user credentials.
Technical details
Crypt::ScryptKDF versions through 0.010 contain a CWE-338 vulnerability where the random_bytes function fails safely. When preferred CSPRNG modules (such as Crypt::PRNG, Crypt::OpenSSL::Random, Net::SSLeay, Crypt::Random, or Bytes::Random::Secure) are not installed in the Perl environment, the library falls back to the built-in rand() function. The rand() function is not cryptographically secure, leading to predictable salt and key generation. This significantly weakens the scrypt-based key derivation process. The issue is resolved in version 0.011 by ensuring a secure entropy source is used or the process fails.
Affected products
- Perl CPAN Crypt::ScryptKDF through 0.010
Timeline
- 2026-05-16: patched: Version 0.011 released to address the issue.
- 2026-05-26: advisory: CVE-2026-8647 published.