Altcha Proof-of-Work obfuscation mode cryptanalytic break
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | altcha | >= 0.8.0, <= 2.2.4 | no fix |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P- Weakness (CWE)
CWE-327- Platform
- npm
- Package
altcha- Disclosed
- 08.12.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-mpmc-qchh-r9q8 - CC BY 4.0
Vulnerability history: altcha
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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