CVE-2025-65849: Altcha Altcha Proof-of-Work Obfuscation Mode Cryptanalytic Vulnerability

MODERATE
Advisory Identifier: GHSA-mpmc-qchh-r9q8
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CWE-327
Published
Advisory Summary

CVE-2025-65849 is a MODERATE altcha proof-of-work obfuscation mode cryptanalytic vulnerability (CWE-327: Use of a Broken or Risky Cryptographic Algorithm) affecting Altcha libraries in the npm ecosystem. The issue involves altcha proof-of-work obfuscation mode cryptanalytic break. Remediation is available in the latest vendor maintenance releases.

CVE-2025-65849 at a Glance

CVE Identifier CVE-2025-65849
GHSA Identifier GHSA-mpmc-qchh-r9q8
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-327: Use of a Broken or Risky Cryptographic Algorithm
Affected Product Altcha
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2025-65849

To remediate this vulnerability, upgrade all affected Altcha dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

altcha fixed: Latest secure release 
npm install altcha@Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls altcha

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2025-65849, inspect your project dependencies using npm:

npm ls altcha

Analyze the terminal output to locate any version of Altcha in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The npm ls altcha command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-327: Use of a Broken or Risky Cryptographic Algorithm, where the product uses a broken or risky cryptographic algorithm or protocol. In Altcha, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2025-65849 Affected Altcha Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
altcha
npm/altcha
npm
≥ 0.8.0
≤ 2.2.4

References

NVD — CVE-2025-65849 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-65849
Altcha Security Information SECURITY
https://altcha.org/docs/v2/obfuscation
Altcha Source Repository REPOSITORY
https://github.com/altcha-org/altcha
Altcha Source Repository REPOSITORY
https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194
Altcha Source Repository REPOSITORY
https://github.com/eternal-flame-AD/altcha-deobfs

Frequently Asked Questions

What is CVE-2025-65849?
CVE-2025-65849 is a security vulnerability in Altcha involving Altcha Proof-of-Work obfuscation mode cryptanalytic break under CWE-327: Use of a Broken or Risky Cryptographic Algorithm.
Which Altcha versions are affected?
Affected versions include releases prior to current release patches across affected packages: altcha.
What version fixes CVE-2025-65849?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is altcha affected?
Yes, altcha is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What CWE is associated with CVE-2025-65849?
CVE-2025-65849 is classified under CWE-327: Use of a Broken or Risky Cryptographic Algorithm (The product uses a broken or risky cryptographic algorithm or protocol.).
How can I check npm dependencies for CVE-2025-65849?
Run the dependency tree command: 'npm ls altcha'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mpmc-qchh-r9q8",
  "modified" : "2025-12-12T19:39:35Z",
  "published" : "2025-12-08T21:30:22Z",
  "aliases" : [ "CVE-2025-65849" ],
  "summary" : "Altcha Proof-of-Work obfuscation mode cryptanalytic break",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "altcha"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.8.0"
      }, {
        "last_affected" : "2.2.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-65849"
  }, {
    "type" : "WEB",
    "url" : "https://altcha.org/docs/v2/obfuscation"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/altcha-org/altcha"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/eternal-flame-AD/altcha-deobfs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-327" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-09T14:26:12Z",
    "nvd_published_at" : "2025-12-08T19:15:50Z"
  }
}