# CVE-2025-65951: Inside Track / Entropy Derby Timelock Encryption Bypassed via Pre-Computed VDF Output Leakage

> Attackers bypass timelock encryption in a betting engine by pre-computing VDF outputs, allowing immediate decryption of bets.

- **Severity:** High 8.7 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Nov 2025
- **Updated:** 25 Nov 2025
- **Also known as:** GHSA-pm54-f847-w4mh

## What is CVE-2025-65951?

CVE-2025-65951 is a high-severity vulnerability in mescuwa entropy-derby, published on 25 Nov 2025. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Inside Track / Entropy Derby is a research-grade horse-racing betting engine. Prior to commit 2d38d2f, the VDF-based timelock encryption system fails to enforce sequential delay against the betting operator. Bettors pre-compute the entire Wesolowski VDF and include vdfOutputHex in their encrypted bet ticket, allowing the house to decrypt immediately using fast proof verification instead of expensive VDF evaluation. This issue has been patched via commit 2d38d2f.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2025-65951?


## How do I fix CVE-2025-65951?

No fix has been published for CVE-2025-65951 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-65951 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-65951 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-65951 and fix it if it is affected.

What it is: CVE-2025-65951 is a high-severity vulnerability in mescuwa entropy-derby, published on 25 Nov 2025. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-65951 exists.

Affected product: mescuwa entropy-derby. 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-2025-65951/ (Markdown: https://insights.sbomify.com/CVE-2025-65951/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-65951
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-65951
- OSV: https://osv.dev/vulnerability/CVE-2025-65951

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-65951/
Summaries are generated and may contain mistakes; the official description above is the record.