Concierge
CVE-2026-2439
CRITICAL
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Perl Concierge::Sessions 0.8.1-0.8.4 generates insecure session IDs using weak randomness, enabling session prediction.
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Concierge::Sessions versions 0.8.1 through 0.8.4 for Perl with uuidgen command missing or failing, forcing silent fallback to insecure Perl rand() function for session ID generation. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 9.8 with patch. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker predicts session tokens and takes over user sessions. |
| Remediation | Update to 0.8.5+. Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all systems running Concierge::Sessions and identify affected versions. …
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External POC / Exploit Code
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