CRITICAL CVSS 9.8
Published: 2026-03-03

CVE-2026-3136

google cloud_build Security Advisory (CVE-2026-3136)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-3136 impacting google cloud_build. Evaluated with CVSS Base Score of 9.8 (CRITICAL).

Original NVD Description

Source: NIST NVD
An improper authorization vulnerability in GitHub Trigger Comment Control in Google Cloud Build prior to 2026-1-26 allows a remote attacker to execute arbitrary code in the build environment. This vulnerability was patched on 26 January 2026, and no customer action is needed.

📊 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
None (PR:N)
Unauthenticated execution
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
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product google / cloud_build
Affected Versions *
Weakness Enumeration CWE-863

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-2026-3136 impacting google cloud_build.

⚡ Nuclei Detection Template (YAML) cve-2026-3136.yaml
id: cve-2026-3136

info:
  name: google cloud_build - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-3136 affecting google cloud_build.
    Evaluation: An improper authorization vulnerability in GitHub Trigger Comment Control in Google Cloud Build prior to 2026-1-26 allows a remote attacker to execute...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-3136
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-3136
    cwe-id: CWE-863
  tags: cve,cve-2026-3136,google,cloud_build,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "cloud_build"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-3136.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-3136
# Target: google cloud_build | CVSS: 9.8 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-3136 (google cloud_build)...")
    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 google cloud_build 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-2026-3136.sh
# Recommended Remediation & Patching Commands for CVE-2026-3136
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install cloud_build 2>/dev/null || \
sudo dnf upgrade cloud_build 2>/dev/null || \
sudo yum update cloud_build

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

# 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.

🔗 Verified Technical References

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

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-3136 in google cloud_build?

Review vendor-specific security notices and update google cloud_build 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-2026-3136?

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-2026-3136?

CVE-2026-3136 is classified with a CVSS 3.1 Base Score of 9.8 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.8
CRITICAL SEVERITY
CVE ID CVE-2026-3136
Weakness CWE-863
Vendor google
Product cloud_build
Published 2026-03-03
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H