CVE-2026-8647 MIK CVE debrief

Who should care

Organizations running Perl applications that use Crypt::ScryptKDF for password hashing, key derivation, or cryptographic operations; DevOps teams managing Perl module dependencies; security auditors reviewing cryptographic implementations in Perl codebases

Technical summary

Crypt::ScryptKDF is a Perl module implementing the scrypt key derivation function. Versions through 0.010 contained a security vulnerability in the random_bytes function, which provides salt material for key derivation. When no cryptographically secure pseudo-random number generator (CSPRNG) module was available in the Perl environment, the function fell back to Perl's built-in rand() function. This fallback is cryptographically insecure as rand() is not designed for security-sensitive operations and produces predictable output. The vulnerability affects salt generation, potentially allowing attackers with knowledge of the random state to predict derived keys. The issue was resolved in version 0.011 by removing the insecure fallback mechanism.

Defensive priority

high

Recommended defensive actions

• Upgrade to Crypt::ScryptKDF version 0.011 or later, which removes the insecure fallback to Perl's built-in rand() function
• Verify that at least one cryptographically secure random number generator module is installed: Crypt::PRNG, Crypt::OpenSSL::Random, Net::SSLeay, Crypt::Random, or Bytes::Random::Secure
• Audit existing deployments to confirm no reliance on the insecure fallback behavior in versions ≤0.010
• Review applications using Crypt::ScryptKDF for key derivation to ensure salt generation uses CSPRNG-backed sources
• Monitor for updated security guidance from the Perl security community via oss-security

Evidence notes

The vulnerability was disclosed on oss-security on 2026-05-26. The fix is available in version 0.011. The weakness is classified as CWE-338 (Use of Cryptographically Weak PRNG).

Official resources