# CVE-2026-2439

## Summary

- **CVE ID:** CVE-2026-2439
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** CWE-340, CWE-338
- **Published:** Feb 16, 2026
- **Last Modified:** Sep 17, 2026

## 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 (0.8.1)

## References

- [CNA](https://metacpan.org/release/BVA/Concierge-Sessions-v0.8.4/diff/BVA/Concierge-Sessions-v0.8.5#lib/Concierge/Sessions/Base.pm)
- [CNA](https://security.metacpan.org/docs/guides/random-data-for-security.html)
- [CNA](https://www.rfc-editor.org/rfc/rfc9562.html#name-security-considerations)
- [CNA](https://perldoc.perl.org/5.42.0/functions/rand)
- [CNA](https://github.com/bwva/Concierge-Sessions/commit/20bb28e92e8fba307c4ff8264701c215be65e73b)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.42%
- **EPSS Percentile:** 35.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._