CVE-2025-65849CRITICAL 9.1EPSS p8.6%

CVE-2025-65849CVE-2025-65849

Description

A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction. NOTE: this is disputed by the Supplier because the product's objective is "to discourage automated scraping / bots, not guarantee resistance to determined attackers." The documentation states “the goal is not to provide a secure cryptographic algorithm but to use a proof-of-work mechanism that allows any capable device to decrypt the hidden data.”

Scoring

CVSS 3.19.1 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS0.19% probability of exploitation · percentile 8.6% · 2026-06-19T12:03:05Z
Published2025-12-08
Last modified2026-04-15

Underlying weaknesses· 1

CWE-327

References

  1. https://altcha.org/docs/v2/obfuscation/
  2. https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194
  3. https://github.com/eternal-flame-AD/altcha-deobfs

1

TypeTargetConfidenceTier
WeaknessUse of a Broken or Risky Cryptographic Algorithmcwe-3270%live

Related by meaning· 6

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.