MEDIUM CVSS 6.5
Published: 2026-05-26

CVE-2026-40564

apache flink_kubernetes_operator Security Advisory (CVE-2026-40564)
โ†— Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-40564 impacting apache flink_kubernetes_operator. Evaluated with CVSS Base Score of 6.5 (MEDIUM).

Original NVD Description

Source: NIST NVD
Files or Directories Accessible to External Parties, Server-Side Request Forgery (SSRF) vulnerability in Apache Flink Kubernetes Operator. The FlinkSessionJob jarURI is currently not validated so that it points to user-owned files or addresses.ย ย This lets a user with CR create permissions read files from the operator pod's filesystem and pull content from any backing store reachable through Flink's pluggable filesystem layer and access them through the submitted Flink job. Furthermore for fetching from http/https addressesย there is currently no allowlist on the URI scheme, no host check, no IP-range restriction, and no protection against pointing the URI at internal or link-local addresses.This issue affects Apache Flink Kubernetes Operator: from 1.3.0 before 1.15.0. Users are recommended to upgrade to version 1.15.0, which fixes the issue.

๐Ÿ“Š 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
None (I:N)
No system modification impact
Availability
None (A:N)
No system availability impact

๐ŸŽฏ Affected Versions Matrix

Affected Product apache / flink_kubernetes_operator
Affected Versions *
Weakness Enumeration CWE-552

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-2026-40564 impacting apache flink_kubernetes_operator.

โšก Nuclei Detection Template (YAML) cve-2026-40564.yaml
id: cve-2026-40564

info:
  name: apache flink_kubernetes_operator - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-40564 affecting apache flink_kubernetes_operator.
    Evaluation: Files or Directories Accessible to External Parties, Server-Side Request Forgery (SSRF) vulnerability in Apache Flink Kubernetes Operator.

The FlinkS...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-40564
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 6.5
    cve-id: CVE-2026-40564
    cwe-id: CWE-552
  tags: cve,cve-2026-40564,apache,flink_kubernetes_operator,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "flink_kubernetes_operator"
        part: body
๐Ÿ PoC Exploit & Verification Probe (Python 3) poc_cve-2026-40564.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-40564
# Target: apache flink_kubernetes_operator | 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-2026-40564 (apache flink_kubernetes_operator)...")
    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 flink_kubernetes_operator 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-2026-40564.sh
# Recommended Remediation & Patching Commands for CVE-2026-40564
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install flink_kubernetes_operator 2>/dev/null || \
sudo dnf upgrade flink_kubernetes_operator 2>/dev/null || \
sudo yum update flink_kubernetes_operator

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

# 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-2026-40564 in apache flink_kubernetes_operator?

Review vendor-specific security notices and update apache flink_kubernetes_operator 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-2026-40564?

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-2026-40564?

CVE-2026-40564 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-2026-40564
Weakness CWE-552
Vendor apache
Product flink_kubernetes_operator
Published 2026-05-26
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N