Vulnerability · Published Jul 16, 2025 · Assigned by CPANSec
CVE-2025-40918Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely
Medium 6.5
In plain English
A medium-severity security flaw in Authen::SASL::Perl::DIGEST_MD5 from EHUELS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | perl-authen-sasl | 2.1900 | ALPINE-CVE-2025-40918 |
| Debian:12 | libauthen-sasl-perl | no fix listed | DEBIAN-CVE-2025-40918 |
| Debian:13 | libauthen-sasl-perl | no fix listed | DEBIAN-CVE-2025-40918 |
| Debian:14 | libauthen-sasl-perl | 2.1900-1 | DEBIAN-CVE-2025-40918 |
| Ubuntu:22.04:LTS | libauthen-sasl-perl | no fix listed | UBUNTU-CVE-2025-40918 |
| Ubuntu:24.04:LTS | libauthen-sasl-perl | no fix listed | UBUNTU-CVE-2025-40918 |
| Ubuntu:25.10 | libauthen-sasl-perl | no fix listed | UBUNTU-CVE-2025-40918 |
| Ubuntu:26.04:LTS | libauthen-sasl-perl | no fix listed | UBUNTU-CVE-2025-40918 |
| Ubuntu:26.10 | libauthen-sasl-perl | no fix listed | UBUNTU-CVE-2025-40918 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| EHUELS | Authen::SASL::Perl::DIGEST_MD5 | 2.04 – through 2.1800 |
Weakness: CWE-340, CWE-338 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
References
- https://metacpan.org/release/EHUELS/Authen-SASL-2.1900/changes
- https://metacpan.org/dist/Authen-SASL/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L263
- https://datatracker.ietf.org/doc/html/rfc2831
- https://security.metacpan.org/patches/A/Authen-SASL/2.1800/CVE-2025-40918-r1.patch patch
- https://github.com/gbarr/perl-authen-sasl/pull/22 issue-tracking
- http://www.openwall.com/lists/oss-security/2025/07/16/5