Vulnerability Description
Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely. The cnonce (client nonce) is generated from an MD5 hash of the PID, the epoch time and the built-in rand function. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. According to RFC 2831, The cnonce-value is an opaque quoted string value provided by the client and used by both client and server to avoid chosen plaintext attacks, and to provide mutual authentication. The security of the implementation depends on a good choice. It is RECOMMENDED that it contain at least 64 bits of entropy.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://datatracker.ietf.org/doc/html/rfc2831
- https://github.com/gbarr/perl-authen-sasl/pull/22
- https://metacpan.org/dist/Authen-SASL/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#
- https://metacpan.org/release/EHUELS/Authen-SASL-2.1900/changes
- https://security.metacpan.org/patches/A/Authen-SASL/2.1800/CVE-2025-40918-r1.pat
- http://www.openwall.com/lists/oss-security/2025/07/16/5
FAQ
What is CVE-2025-40918?
CVE-2025-40918 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely. The cnonce (client nonce) is generated from an MD5 hash of the PID, the epoch time and the built-...
How severe is CVE-2025-40918?
CVE-2025-40918 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-40918?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.