CVE-2025-40920 identifies a security vulnerability in the Catalyst::Authentication::Credential::HTTP module versions 1.018 and earlier, specifically related to the generation of nonces used in HTTP authentication. The module relies on the Perl Data::UUID library to generate these nonces. However, Data::UUID produces version 3 UUIDs, which are name-based and generated from known information using MD5 hashing, making them predictable and unsuitable for cryptographic purposes. This violates best practices outlined in RFC 7616, which mandates that nonces used in HTTP Digest Authentication should be generated from strong cryptographic random sources to prevent replay and impersonation attacks. The vulnerability is categorized under CWE-340 (Generation of Predictable Numbers or Identifiers), indicating that the nonces can be predicted or reproduced by an attacker. Because nonces are critical for preventing replay attacks and ensuring the freshness of authentication requests, predictable nonces can allow attackers to replay authentication messages or potentially impersonate legitimate users. The vulnerability affects the Catalyst::Authentication::Credential::HTTP Perl module, commonly used in web applications built with the Catalyst framework for HTTP authentication. No patch links are currently available, and no known exploits have been reported in the wild as of the publication date. The CVSS score is not assigned, but the vulnerability is significant due to the cryptographic weakness in nonce generation.

For European organizations using web applications built on the Catalyst framework with the vulnerable Catalyst::Authentication::Credential::HTTP module, this vulnerability could lead to authentication bypass or replay attacks. Attackers could predict nonces and reuse authentication tokens, potentially gaining unauthorized access to sensitive systems or data. This undermines the confidentiality and integrity of user sessions and could facilitate lateral movement within networks. Organizations handling sensitive personal data, financial information, or critical infrastructure services are particularly at risk. The vulnerability could also affect compliance with GDPR and other European data protection regulations if unauthorized access leads to data breaches. Although no exploits are currently known in the wild, the predictability of nonces is a fundamental cryptographic flaw that could be leveraged by attackers with network access or the ability to intercept authentication traffic. The impact is heightened in environments where Catalyst-based applications are exposed to the internet or untrusted networks, increasing the attack surface.

European organizations should immediately audit their use of the Catalyst::Authentication::Credential::HTTP module to identify affected versions (1.018 and earlier). Since no official patch is currently available, organizations should implement the following mitigations: 1) Replace the nonce generation mechanism with a cryptographically secure random number generator compliant with RFC 7616, such as using Perl modules like Crypt::URandom or Crypt::Random to generate nonces. 2) Apply additional layers of security, such as enforcing TLS to protect authentication traffic from interception and replay. 3) Implement monitoring and anomaly detection to identify unusual authentication patterns indicative of replay or impersonation attempts. 4) Where possible, upgrade to newer versions of Catalyst modules or alternative authentication mechanisms that do not rely on predictable nonces. 5) Engage with the vendor or open-source maintainers to prioritize a patch release addressing this vulnerability. 6) Conduct penetration testing focused on authentication mechanisms to validate the effectiveness of mitigations.