HIGH CVSS 7.1
Published: 2026-05-07

CVE-2026-42010

gnu gnutls Security Advisory (CVE-2026-42010)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-42010 impacting gnu gnutls. Evaluated with CVSS Base Score of 7.1 (HIGH).

Original NVD Description

Source: NIST NVD
A flaw was found in gnutls. Servers configured with RSA-PSK (Rivest–Shamir–Adleman – Pre-Shared Key) wrongfully matched usernames containing a NUL character with truncated usernames. A remote attacker could exploit this by sending a specially crafted username, leading to an authentication bypass. This vulnerability allows an attacker to gain unauthorized access by circumventing the authentication process.

📊 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
High (C:H)
Total information disclosure
Integrity
Low (I:L)
Partial data modification possible
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product gnu / gnutls
Affected Versions -
Weakness Enumeration CWE-170

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-2026-42010 impacting gnu gnutls.

⚡ Nuclei Detection Template (YAML) cve-2026-42010.yaml
id: cve-2026-42010

info:
  name: gnu gnutls - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-42010 affecting gnu gnutls.
    Evaluation: A flaw was found in gnutls. Servers configured with RSA-PSK (Rivest–Shamir–Adleman – Pre-Shared Key) wrongfully matched usernames containing a NUL cha...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-42010
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
    cvss-score: 7.1
    cve-id: CVE-2026-42010
    cwe-id: CWE-170
  tags: cve,cve-2026-42010,gnu,gnutls,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "gnutls"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-42010.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-42010
# Target: gnu gnutls | CVSS: 7.1 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-42010 (gnu gnutls)...")
    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 gnu gnutls 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-2026-42010.sh
# Recommended Remediation & Patching Commands for CVE-2026-42010
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install gnutls 2>/dev/null || \
sudo dnf upgrade gnutls 2>/dev/null || \
sudo yum update gnutls

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

# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-42010 in gnu gnutls?

Review vendor-specific security notices and update gnu gnutls 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-2026-42010?

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-2026-42010?

CVE-2026-42010 is classified with a CVSS 3.1 Base Score of 7.1 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.1
HIGH SEVERITY
CVE ID CVE-2026-42010
Weakness CWE-170
Vendor gnu
Product gnutls
Published 2026-05-07
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N