CVE-2025-40918

Name	CVE-2025-40918
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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1109406

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libauthen-sasl-perl (PTS)	bullseye	2.1600-1.1	vulnerable
	bookworm	2.1600-3	vulnerable
	sid, trixie	2.1700-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libauthen-sasl-perl	source	(unstable)	(unfixed)			1109406

Notes

[bookworm] - libauthen-sasl-perl <no-dsa> (Minor issue)
[bullseye] - libauthen-sasl-perl <postponed> (Minor issue, weak entropy for historic DIGEST-MD5 mech)
https://lists.security.metacpan.org/cve-announce/msg/31224910/
https://security.metacpan.org/patches/A/Authen-SASL/2.1800/CVE-2025-40918-r1.patch
https://github.com/gbarr/perl-authen-sasl/pull/22