LOW CVSS 3.7
Published: 2026-07-09

CVE-2026-12590

openjsf body-parser Security Advisory (CVE-2026-12590)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-12590 impacting openjsf body-parser. Evaluated with CVSS Base Score of 3.7 (LOW).

Original NVD Description

Source: NIST NVD
Impact: In body-parser versions prior to 1.20.6 (1.x line) and 2.3.0 (2.x line), when the parser is configured with an invalid limit option value such as an unparseable string or NaN, bytes.parse returns null and the request body size check is silently skipped. Applications that rely on limit as their primary safeguard against oversized request bodies will accept arbitrarily large payloads, leading to excessive memory and CPU usage and denial of service. Patches: This issue is fixed in body-parser 1.20.6 and 2.3.0. After the fix, invalid limit values throw a clear error at parser construction time instead of silently disabling enforcement, while null and undefined continue to fall back to the default limit of 100kb. Workarounds: Validate the limit value before passing it to body-parser. For example, parse the value at startup and reject any configuration where the result is null or a non-finite number.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
High (AC:H)
Depends on race conditions or environment
Privileges Required
None (PR:N)
Unauthenticated execution
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
None (I:N)
No system modification impact
Availability
Low (A:L)
Partial service performance degradation

🎯 Affected Versions Matrix

Affected Product openjsf / body-parser
Affected Versions *
Weakness Enumeration CWE-770

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-2026-12590 impacting openjsf body-parser.

⚡ Nuclei Detection Template (YAML) cve-2026-12590.yaml
id: cve-2026-12590

info:
  name: openjsf body-parser - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: low
  description: |
    Automated signature & scanner for CVE-2026-12590 affecting openjsf body-parser.
    Evaluation: Impact: In body-parser versions prior to 1.20.6 (1.x line) and 2.3.0 (2.x line), when the parser is configured with an invalid limit option value such...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-12590
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
    cvss-score: 3.7
    cve-id: CVE-2026-12590
    cwe-id: CWE-770
  tags: cve,cve-2026-12590,openjsf,body-parser,low

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "body-parser"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-12590.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-12590
# Target: openjsf body-parser | CVSS: 3.7 (LOW)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-12590 (openjsf body-parser)...")
    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 openjsf body-parser 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-2026-12590.sh
# Recommended Remediation & Patching Commands for CVE-2026-12590
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install body-parser 2>/dev/null || \
sudo dnf upgrade body-parser 2>/dev/null || \
sudo yum update body-parser

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

# 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-2026-12590 in openjsf body-parser?

Review vendor-specific security notices and update openjsf body-parser 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-2026-12590?

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-2026-12590?

CVE-2026-12590 is classified with a CVSS 3.1 Base Score of 3.7 (LOW). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
3.7
LOW SEVERITY
CVE ID CVE-2026-12590
Weakness CWE-770
Vendor openjsf
Product body-parser
Published 2026-07-09
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L