CVE-2026-2439: BVA Concierge::Sessions · Generation of Predictable Numbers or Identifiers
Affects BVA Concierge::SessionsSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical : upgrade to 0.8.5 as a priority.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.8.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Upgrade Concierge::Sessions and Concierge-Sessions to 0.8.5.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| BVAConcierge::Sessions | Affected
| Fixed in
|
GitHubConcierge-Sessionspkg:github/Concierge-SessionsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To mitigate CVE-2026-2439, organizations should take the following specific actions: 1) Upgrade Concierge::Sessions to version 0.8.5 or later where the session ID generation method is corrected to use cryptographically secure random number generators explicitly. 2) If upgrading is not immediately possible, patch the generate_session_id function to explicitly invoke uuidgen with the --random option to ensure random UUIDs are generated, or replace uuidgen calls with a secure, cryptographically strong random number generator available in Perl (e.g., Crypt::URandom or Crypt::Random modules). 3) Implement monitoring to detect anomalous session ID patterns or repeated failed session validation attempts that may indicate guessing attacks. 4) Enforce short session lifetimes and implement additional authentication factors to reduce the window of opportunity for attackers. 5) Conduct code reviews and security audits on session management components to verify the use of secure randomness. 6) Educate developers and administrators about the risks of relying on system commands without explicit security parameters and the dangers of fallback to insecure functions without warnings. These targeted measures go beyond generic advice by focusing on the root cause and operational detection.
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.
References
- metacpan.org/release/BVA/Concierge-Sessions-v0.8.4/diff/BVA/Concierge-Sessions-v0.8.5 (opens in a new tab)
- security.metacpan.org/docs/guides/random-data-for-security.html (opens in a new tab)
- rfc-editor.org/rfc/rfc9562.html (opens in a new tab)
- perldoc.perl.org/5.42.0/functions/rand (opens in a new tab)
- github.com/bwva/Concierge-Sessions/commit/20bb28e92e8fba307c4ff8264701c215be65e73b (opens in a new tab)