CVE-2026-2439: Concierge::Sessions versions from 0.8.1 before 0.8.5 for Perl generate insecure session ids

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-16 · updated 2026-06-17
Weakness: CWE-338

Description

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 Perl's 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.

Affected products

BVA Concierge::Sessions: from 0.8.1 before 0.8.5 — fixed in 0.8.5

How to fix

Upgrade to a fixed version: BVA Concierge::Sessions 0.8.5. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-2439 or the next vulnerability affects your stack