# CVE-2026-8647: Perl Crypt::ScryptKDF weak PRNG use in random_bytes

Source: https://junglewise.ai/threats/cve-2026-8647-perl-crypt-scryptkdf-weak-prng-use-in-random-bytes  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-26. Updated: 2026-05-26  
License: CC BY 4.0 with a link back

CVE-2026-8647 · Severity: info · CVSS 3.3 · Published 2026-05-26

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.

Vendors: [Perl CPAN](https://junglewise.ai/threats/vendors/perl-cpan).

## Quick answers

**Is CVE-2026-8647 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8647 being exploited in the wild.

**How severe is CVE-2026-8647?** Informational severity, with a CVSS score of 3.3, published 26 May 2026.

**Which products and versions are affected?** Perl CPAN Crypt::ScryptKDF through 0.010.

**Is there a fix for CVE-2026-8647?** A patch was published on 2026-05-16: Version 0.011 released to address the issue. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-8647 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-8647?** Check whether you run Perl CPAN Crypt::ScryptKDF at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## 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.

## References

- [https://metacpan.org/release/MIK/Crypt-ScryptKDF-0.011/changes](https://metacpan.org/release/MIK/Crypt-ScryptKDF-0.011/changes)
- [https://metacpan.org/release/MIK/Crypt-ScryptKDF-0.011/diff/MIK/Crypt-ScryptKDF-0.010](https://metacpan.org/release/MIK/Crypt-ScryptKDF-0.011/diff/MIK/Crypt-ScryptKDF-0.010)