HIGH CVSS 8.1
Published: 2026-04-21

CVE-2026-40868

kyverno kyverno Security Advisory (CVE-2026-40868)
โ†— Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-40868?
๐Ÿ”ฌ Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-40868 impacting kyverno kyverno. Evaluated with CVSS Base Score of 8.1 (HIGH).

Original NVD Description

Source: NIST NVD
Kyverno is a policy engine designed for cloud native platform engineering teams. Prior to 1.16.4, kyvernoโ€™s apiCall servicecall helper implicitly injects Authorization: Bearer ... using the kyverno controller serviceaccount token when a policy does not explicitly set an Authorization header. Because context.apiCall.service.url is policy-controlled, this can send the kyverno serviceaccount token to an attacker-controlled endpoint (confused deputy). Namespaced policies are blocked from servicecall usage by the namespaced urlPath gate in pkg/engine/apicall/apiCall.go, so this report is scoped to ClusterPolicy and global context usage. This vulnerability is fixed in 1.16.4.

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
High (I:H)
Total modification of target system
Availability
None (A:N)
No system availability impact

๐ŸŽฏ Affected Versions Matrix

Affected Product kyverno / kyverno
Affected Versions *
Weakness Enumeration CWE-922

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-2026-40868 impacting kyverno kyverno.

โšก Nuclei Detection Template (YAML) cve-2026-40868.yaml
id: cve-2026-40868

info:
  name: kyverno kyverno - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-40868 affecting kyverno kyverno.
    Evaluation: Kyverno is a policy engine designed for cloud native platform engineering teams. Prior to 1.16.4, kyvernoโ€™s apiCall servicecall helper implicitly inje...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-40868
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
    cvss-score: 8.1
    cve-id: CVE-2026-40868
    cwe-id: CWE-922
  tags: cve,cve-2026-40868,kyverno,kyverno,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "kyverno"
        part: body
๐Ÿ PoC Exploit & Verification Probe (Python 3) poc_cve-2026-40868.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-40868
# Target: kyverno kyverno | CVSS: 8.1 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-40868 (kyverno kyverno)...")
    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 kyverno kyverno 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-2026-40868.sh
# Recommended Remediation & Patching Commands for CVE-2026-40868
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install kyverno 2>/dev/null || \
sudo dnf upgrade kyverno 2>/dev/null || \
sudo yum update kyverno

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

# 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-2026-40868 in kyverno kyverno?

Review vendor-specific security notices and update kyverno kyverno 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-2026-40868?

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-2026-40868?

CVE-2026-40868 is classified with a CVSS 3.1 Base Score of 8.1 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.1
HIGH SEVERITY
CVE ID CVE-2026-40868
Weakness CWE-922
Vendor kyverno
Product kyverno
Published 2026-04-21
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N