HIGH CVSS 8.6
Published: 2022-09-29

CVE-2022-39250

matrix javascript_sdk Security Advisory (CVE-2022-39250)
โ†— Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2022-39250 impacting matrix javascript_sdk. Evaluated with CVSS Base Score of 8.6 (HIGH).

Original NVD Description

Source: NIST NVD
Matrix JavaScript SDK is the Matrix Client-Server software development kit (SDK) for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver could interfere with the verification flow between two users, injecting its own cross-signing user identity in place of one of the usersโ€™ identities. This would lead to the other device trusting/verifying the user identity under the control of the homeserver instead of the intended one. The vulnerability is a bug in the matrix-js-sdk, caused by checking and signing user identities and devices in two separate steps, and inadequately fixing the keys to be signed between those steps. Even though the attack is partly made possible due to the design decision of treating cross-signing user identities as Matrix devices on the server side (with their device ID set to the public part of the user identity key), no other examined implementations were vulnerable. Starting with version 19.7.0, the matrix-js-sdk has been modified to double check that the key signed is the one that was verified instead of just referencing the key by ID. An additional check has been made to report an error when one of the device ID matches a cross-signing key. As this attack requires coordination between a malicious homeserver and an attacker, those who trust their homeservers do not need a particular workaround.

๐Ÿ“Š CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
Scope
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
High (I:H)
Total modification of target system
Availability
None (A:N)
No system availability impact

๐ŸŽฏ Affected Versions Matrix

Affected Product matrix / javascript_sdk
Affected Versions *
Weakness Enumeration CWE-287

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2022-39250 impacting matrix javascript_sdk.

โšก Nuclei Detection Template (YAML) cve-2022-39250.yaml
id: cve-2022-39250

info:
  name: matrix javascript_sdk - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2022-39250 affecting matrix javascript_sdk.
    Evaluation: Matrix JavaScript SDK is the Matrix Client-Server software development kit (SDK) for JavaScript. Prior to version 19.7.0, an attacker cooperating with...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2022-39250
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
    cvss-score: 8.6
    cve-id: CVE-2022-39250
    cwe-id: CWE-287
  tags: cve,cve-2022-39250,matrix,javascript_sdk,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "javascript_sdk"
        part: body
๐Ÿ PoC Exploit & Verification Probe (Python 3) poc_cve-2022-39250.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2022-39250
# Target: matrix javascript_sdk | CVSS: 8.6 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2022-39250 (matrix javascript_sdk)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against matrix javascript_sdk scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
๐Ÿ›ก๏ธ Quick Patch & Remediation Script (Bash) patch_cve-2022-39250.sh
# Recommended Remediation & Patching Commands for CVE-2022-39250
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install javascript_sdk 2>/dev/null || \
sudo dnf upgrade javascript_sdk 2>/dev/null || \
sudo yum update javascript_sdk

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i javascript_sdk 2>/dev/null || rpm -qa | grep -i javascript_sdk

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

๐Ÿ›ก๏ธ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
โš ๏ธ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

โ“ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2022-39250 in matrix javascript_sdk?

Review vendor-specific security notices and update matrix javascript_sdk packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2022-39250?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2022-39250?

CVE-2022-39250 is classified with a CVSS 3.1 Base Score of 8.6 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.6
HIGH SEVERITY
CVE ID CVE-2022-39250
Weakness CWE-287
Vendor matrix
Product javascript_sdk
Published 2022-09-29
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N