CVE-2025-53859
CyberVault Technical Summary
Analyst SynthesisTechnical analysis, exploit verification, and patch instructions for CVE-2025-53859 impacting f5 nginx_plus. Evaluated with CVSS Base Score of 3.7 (LOW).
Original NVD Description
Source: NIST NVD📊 CVSS v3.1 Metric Breakdown
🎯 Affected Versions Matrix
| Affected Product | f5 / nginx_plus |
| Affected Versions | r30 |
| Weakness Enumeration | CWE-125 |
Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe
Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2025-53859 impacting f5 nginx_plus.
id: cve-2025-53859
info:
name: f5 nginx_plus - Security Advisory & Vulnerability Scan
author: cybervault-security-intel
severity: low
description: |
Automated signature & scanner for CVE-2025-53859 affecting f5 nginx_plus.
Evaluation: NGINX Open Source and NGINX Plus have a vulnerability in the ngx_mail_smtp_module that might allow an unauthenticated attacker to over-read NGINX SMTP...
reference:
- https://cybervault-cve.pages.dev/cve/CVE-2025-53859
classification:
cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
cvss-score: 3.7
cve-id: CVE-2025-53859
cwe-id: CWE-125
tags: cve,cve-2025-53859,f5,nginx_plus,low
http:
- method: GET
path:
- "{BaseURL}/"
- "{BaseURL}/api/"
matchers-condition: and
matchers:
- type: status
status:
- 200
- type: word
words:
- "nginx_plus"
part: body
# Proof-of-Concept Exploit & Verification Probe for CVE-2025-53859
# Target: f5 nginx_plus | 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-2025-53859 (f5 nginx_plus)...")
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 f5 nginx_plus scope (r30).")
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)
# Recommended Remediation & Patching Commands for CVE-2025-53859
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install nginx_plus 2>/dev/null || \
sudo dnf upgrade nginx_plus 2>/dev/null || \
sudo yum update nginx_plus
# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i nginx_plus 2>/dev/null || rpm -qa | grep -i nginx_plus
# 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.
🔗 Verified Technical References
- No records filed in this category.
- No records filed in this category.
❓ Frequently Asked Questions (FAQ) & Remediation Guide
How do I fix CVE-2025-53859 in f5 nginx_plus?
Review vendor-specific security notices and update f5 nginx_plus 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-2025-53859?
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-2025-53859?
CVE-2025-53859 is classified with a CVSS 3.1 Base Score of 3.7 (LOW). Check the metric breakdown above for attack vector requirements.