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

> Attackers can guess insecure session IDs generated by the Concierge::Sessions Perl library, leading to unauthorized access and account takeover.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Feb 2026
- **Updated:** 17 Feb 2026
- **Also known as:** GHSA-9gww-cr64-679c

## What is CVE-2026-2439?

CVE-2026-2439 is a critical vulnerability in BVA Concierge::Sessions, published on 16 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-340 (Generation of Predictable Numbers or Identifiers), CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG))

## Which versions are affected by CVE-2026-2439?

It affects 1 product.


Products: Bva Concierge\.

## How do I fix CVE-2026-2439?

No fix has been published for CVE-2026-2439 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2439 being exploited?

There is no known exploitation of CVE-2026-2439 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2439 and fix it if it is affected.

What it is: CVE-2026-2439 is a critical vulnerability in BVA Concierge::Sessions, published on 16 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-2439 in the wild and no public exploit code.

Affected product: BVA Concierge::Sessions. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-2439/ (Markdown: https://insights.sbomify.com/CVE-2026-2439/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2439
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2439
- OSV: https://osv.dev/vulnerability/CVE-2026-2439

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2439/
Summaries are generated and may contain mistakes; the official description above is the record.