CVE-2026-2439

NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-2439
CWE	https://cwe.mitre.org/data/definitions/338.html

Concierge::Sessions versions from 0.8.1 before 0.8.5 for Perl generate insecure session ids. The generate_session_id function in Concierge::Sessions::Base defaults to using the uuidgen command to generate a UUID, with a fallback to using Perls built-in rand function. Neither of these methods are secure, and attackers are able to guess session_ids that can grant them access to systems. Specifically,

There is no warning when uuidgen fails. The software can be quietly using the fallback rand() function with no warnings if the command fails for any reason.
The uuidgen command will generate a time-based UUID if the system does not have a high-quality random number source, because the call does not explicitly specify the –random option. Note that the system time is shared in HTTP responses.
UUIDs are identifiers whose mere possession grants access, as per RFC 9562.
The output of the built-in rand() function is predictable and unsuitable for security applications.

Weakness

The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG’s algorithm is not cryptographically strong.

Extended Description

When a non-cryptographic PRNG is used in a cryptographic context, it can expose the cryptography to certain types of attacks. Often a pseudo-random number generator (PRNG) is not designed for cryptography. Sometimes a mediocre source of randomness is sufficient or preferable for algorithms that use random numbers. Weak generators generally take less processing power and/or do not use the precious, finite, entropy sources on a system. While such PRNGs might have very useful features, these same features could be used to break the cryptography.

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Weakness

Extended Description

Potential Mitigations

References