# CVE-2025-40918: libauthen-sasl-perl: Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely

CVE-2025-40918 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2025-40918, released July 16, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-40918
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0046
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 16, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libauthen-sasl-perl Debian 14 | 2.1900-1 | [DEBIAN-CVE-2025-40918](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40918.md) | Jul 16, 2025 |
| Linux | perl-Authen-SASL amzn 2023 | 2.16-23.amzn2023.0.3 | [ALAS2023-2025-1156](https://patchblox.com/security/data/fix/linux/alas2023-2025-1156.md) | Aug 18, 2025 |
| Linux | perl-Authen-SASL opensuse-leap 15.6 | 2.16-150000.1.6.1 | [SUSE-SU-2025:03087-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03087-1.md) | Sep 5, 2025 |
| Linux | perl-Authen-SASL opensuse-leap 16.0 | 2.170.0-160000.3.1 | [OPENSUSE-SU-2026:20480-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20480-1.md) | Apr 9, 2026 |
| Linux | perl-Authen-SASL sles 15.6 | 2.16-150000.1.6.1 | [SUSE-SU-2025:03087-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03087-1.md) | Sep 5, 2025 |
| Linux | perl-Authen-SASL sles 15.7 | 2.16-150000.1.6.1 | [SUSE-SU-2025:03087-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03087-1.md) | Sep 5, 2025 |
| Linux | perl-Authen-SASL sles 16.0 | 2.170.0-160000.3.1 | [SUSE-SU-2026:21145-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21145-1.md) | Apr 9, 2026 |
| Linux | perl-Crypt-URandom opensuse-leap 15.6 | 0.540.0-150000.1.3.1 | [SUSE-SU-2025:03087-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03087-1.md) | Sep 5, 2025 |
| Linux | perl-Crypt-URandom opensuse-leap 16.0 | 0.550.0-160000.1.1 | [OPENSUSE-SU-2026:20480-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20480-1.md) | Apr 9, 2026 |
| Linux | perl-Crypt-URandom sles 15.6 | 0.540.0-150000.1.3.1 | [SUSE-SU-2025:03087-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03087-1.md) | Sep 5, 2025 |
| Linux | perl-Crypt-URandom sles 15.7 | 0.540.0-150000.1.3.1 | [SUSE-SU-2025:03087-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03087-1.md) | Sep 5, 2025 |
| Linux | perl-Crypt-URandom sles 16.0 | 0.550.0-160000.1.1 | [SUSE-SU-2026:21145-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21145-1.md) | Apr 9, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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