BaseFortify

Publication date: 2025-12-08

Last updated on: 2025-12-11

Assigner: MITRE

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.”

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-12-08

Last Modified

2025-12-11

Generated

2026-07-06

AI Q&A

2025-12-08

EPSS Evaluated

2026-07-05

NVD

CVE-2025-65849

Affected Vendors & Products

Vendor	Product	Version / Range
altcha	altcha	0.8.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-327	The product uses a broken or risky cryptographic algorithm or protocol.

Attack-Flow Graph

Executive Summary

This vulnerability is a cryptanalytic break in the Altcha Proof-of-Work obfuscation mode version 0.8.0 and later. It allows remote visitors to recover the Proof-of-Work nonce in constant time using mathematical deduction.

Impact Analysis

The vulnerability allows an attacker to recover the Proof-of-Work nonce remotely and quickly, which could undermine the security assumptions of the Proof-of-Work mechanism, potentially enabling attacks that rely on nonce secrecy or integrity.

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