Inside Track / Entropy Derby Timelock Encryption Bypassed via Pre-Computed VDF Output Leakage

published 2025-11-25 11 mo ago modified 2026-10-18 21 d ago also EUVD-2025-199528

cvss: 8.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

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.

Patch / fix

links 1

github.com/mescuwa/entropy-derby@2d38d2f commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 11 mo ago (2025-11-25)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.7	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

Affected products

mescuwa entropy-derby

Classification

Weakness

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

CVE List CVE-2025-65951
NVD CVE-2025-65951

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary