MEDIUM CVSS 6.5
Published: 2026-04-29

CVE-2026-42521

jenkins matrix_authorization_strategy Security Advisory (CVE-2026-42521)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-42521 impacting jenkins matrix_authorization_strategy. Evaluated with CVSS Base Score of 6.5 (MEDIUM).

Original NVD Description

Source: NIST NVD
Jenkins Matrix Authorization Strategy Plugin 2.0-beta-1 through 3.2.9 (both inclusive) invokes parameterless constructors of classes specified in configuration when deserializing inheritance strategies, without restricting the classes that can be instantiated, allowing attackers with Item/Configure permission to instantiate arbitrary types, which may lead to information disclosure or other impacts depending on the classes available on the classpath.

📊 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
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
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

🎯 Affected Versions Matrix

Affected Product jenkins / matrix_authorization_strategy
Affected Versions *
Weakness Enumeration CWE-502

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-2026-42521 impacting jenkins matrix_authorization_strategy.

⚡ Nuclei Detection Template (YAML) cve-2026-42521.yaml
id: cve-2026-42521

info:
  name: jenkins matrix_authorization_strategy - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-42521 affecting jenkins matrix_authorization_strategy.
    Evaluation: Jenkins Matrix Authorization Strategy Plugin 2.0-beta-1 through 3.2.9 (both inclusive) invokes parameterless constructors of classes specified in conf...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-42521
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
    cvss-score: 6.5
    cve-id: CVE-2026-42521
    cwe-id: CWE-502
  tags: cve,cve-2026-42521,jenkins,matrix_authorization_stra,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "matrix_authorization_strategy"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-42521.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-42521
# Target: jenkins matrix_authorization_strategy | CVSS: 6.5 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-42521 (jenkins matrix_authorization_strategy)...")
    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 jenkins matrix_authorization_strategy 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)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-42521.sh
# Recommended Remediation & Patching Commands for CVE-2026-42521
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install matrix_authorization_stra 2>/dev/null || \
sudo dnf upgrade matrix_authorization_stra 2>/dev/null || \
sudo yum update matrix_authorization_stra

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

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

🛡️ 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.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

🔗 Verified Technical References

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-42521 in jenkins matrix_authorization_strategy?

Review vendor-specific security notices and update jenkins matrix_authorization_strategy 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-2026-42521?

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-2026-42521?

CVE-2026-42521 is classified with a CVSS 3.1 Base Score of 6.5 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.5
MEDIUM SEVERITY
CVE ID CVE-2026-42521
Weakness CWE-502
Vendor jenkins
Product matrix_authorization_strategy
Published 2026-04-29
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N