MEDIUM CVSS 4.8
Published: 2026-04-27

CVE-2026-40557

apache storm_prometheus_reporter Security Advisory (CVE-2026-40557)
โ†— Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-40557 impacting apache storm_prometheus_reporter. Evaluated with CVSS Base Score of 4.8 (MEDIUM).

Original NVD Description

Source: NIST NVD
Improper Certificate Validation via Global SSL Context Downgrade in Apache Storm Prometheus Reporter Versions Affected: from 2.6.3 to 2.8.6 Description:ย  In production deployments where an administrator enables storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validationย (by default it is disabled)ย intending to affect only the Prometheus reporter, the undocumented global side effect creates an attack surface across every TLS-protected communication channel in the Storm daemon. The PrometheusPreparableReporter class implements an INSECURE_TRUST_MANAGER that accepts all SSL certificates without validation, with empty checkClientTrusted and checkServerTrusted methods. Most critically, when the storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation configuration option is enabled (default = disabled) for HTTPS Prometheus PushGateway connections, the INSECURE_CONNECTION_FACTORY calls SSLContext.setDefault(sslContext), which globally replaces the JVM's default SSL context rather than applying the insecure context only to the Prometheus connection. This payload flows through storm.yaml configuration โ†’ PrometheusPreparableReporter.prepare() โ†’ INSECURE_CONNECTION_FACTORY โ†’ SSLContext.setDefault(), resulting in a JVM-wide TLS security downgrade. All subsequent HTTPS connections in the process - including ZooKeeper, Thrift, Netty, and UI connections - silently trust all certificates, including self-signed, expired, and attacker-generated ones, enabling man-in-the-middle interception of cluster state, topology submissions, tuple data, and administrative credentials. Mitigation: 2.x users should upgrade to 2.8.7 if the Prometheus Metrics Reporter is used. Prometheus Metrics Reporter Users who cannot upgrade immediately should remove the storm.daemon.metrics.reporter.plugin.prometheus.skip_tls_validation: true setting from their storm.yaml configuration and instead configure a proper truststore containing the PushGateway's certificate.

๐Ÿ“Š 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
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
None (A:N)
No system availability impact

๐ŸŽฏ Affected Versions Matrix

Affected Product apache / storm_prometheus_reporter
Affected Versions *
Weakness Enumeration CWE-295

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-2026-40557 impacting apache storm_prometheus_reporter.

โšก Nuclei Detection Template (YAML) cve-2026-40557.yaml
id: cve-2026-40557

info:
  name: apache storm_prometheus_reporter - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-40557 affecting apache storm_prometheus_reporter.
    Evaluation: Improper Certificate Validation via Global SSL Context Downgrade in Apache Storm Prometheus Reporter


Versions Affected: from 2.6.3 to 2.8.6


Descri...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-40557
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
    cvss-score: 4.8
    cve-id: CVE-2026-40557
    cwe-id: CWE-295
  tags: cve,cve-2026-40557,apache,storm_prometheus_reporter,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "storm_prometheus_reporter"
        part: body
๐Ÿ PoC Exploit & Verification Probe (Python 3) poc_cve-2026-40557.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-40557
# Target: apache storm_prometheus_reporter | CVSS: 4.8 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-40557 (apache storm_prometheus_reporter)...")
    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 apache storm_prometheus_reporter 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-2026-40557.sh
# Recommended Remediation & Patching Commands for CVE-2026-40557
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install storm_prometheus_reporter 2>/dev/null || \
sudo dnf upgrade storm_prometheus_reporter 2>/dev/null || \
sudo yum update storm_prometheus_reporter

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

# 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.

๐Ÿ”— Verified Technical References

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

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

How do I fix CVE-2026-40557 in apache storm_prometheus_reporter?

Review vendor-specific security notices and update apache storm_prometheus_reporter 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-2026-40557?

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-2026-40557?

CVE-2026-40557 is classified with a CVSS 3.1 Base Score of 4.8 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
4.8
MEDIUM SEVERITY
CVE ID CVE-2026-40557
Weakness CWE-295
Vendor apache
Product storm_prometheus_reporter
Published 2026-04-27
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N