What is GHSA-mpmc-qchh-r9q8?

GHSA-mpmc-qchh-r9q8 is a security advisory published by GitHub Security Advisories with Medium severity. Altcha Proof-of-Work obfuscation mode cryptanalytic break

Which CVE IDs does GHSA-mpmc-qchh-r9q8 cover?

GHSA-mpmc-qchh-r9q8 covers the following CVE IDs: CVE-2025-65849. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

Which products are affected by GHSA-mpmc-qchh-r9q8?

GHSA-mpmc-qchh-r9q8 affects 1 product, including: npm/altcha:\u003e= 0.8.0, \u003c= 2.2.4.

GHSA-mpmc-qchh-r9q8Medium

Altcha Proof-of-Work obfuscation mode cryptanalytic break

Vendor

GitHub Security Advisories

Published

December 8, 2025

Last Modified

December 12, 2025

🔗 CVE IDs covered (1)

CVE-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.

🎯 Affected products1

npm/altcha:>= 0.8.0, <= 2.2.4

🔗 References (5)

https://nvd.nist.gov/vuln/detail/CVE-2025-65849
https://altcha.org/docs/v2/obfuscation
https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194
https://github.com/eternal-flame-AD/altcha-deobfs
https://github.com/advisories/GHSA-mpmc-qchh-r9q8