HIGH CVSS 8.8
Published: 2026-05-12

CVE-2026-42844

getgrav grav Security Advisory (CVE-2026-42844)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-42844?
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-42844 impacting getgrav grav. Evaluated with CVSS Base Score of 8.8 (HIGH).

Original NVD Description

Source: NIST NVD
Grav is a file-based Web platform. In Grav 2.0.0-beta.2, a low-privileged authenticated API user with api.media.write can abuse /api/v1/blueprint-upload to write an arbitrary YAML file into user/accounts/, then log in as the newly created account with api.super privileges. This results in full administrative compromise of the Grav API. This vulnerability is fixed in API 1.0.0-beta.17.

📊 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
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product getgrav / grav
Affected Versions 2.0.0
Weakness Enumeration CWE-269

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-2026-42844 impacting getgrav grav.

⚡ Nuclei Detection Template (YAML) cve-2026-42844.yaml
id: cve-2026-42844

info:
  name: getgrav grav - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-42844 affecting getgrav grav.
    Evaluation: Grav is a file-based Web platform. In Grav 2.0.0-beta.2, a low-privileged authenticated API user with api.media.write can abuse /api/v1/blueprint-uplo...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-42844
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.8
    cve-id: CVE-2026-42844
    cwe-id: CWE-269
  tags: cve,cve-2026-42844,getgrav,grav,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "grav"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-42844.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-42844
# Target: getgrav grav | CVSS: 8.8 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-42844 (getgrav grav)...")
    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 getgrav grav scope (2.0.0).")
        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-2026-42844.sh
# Recommended Remediation & Patching Commands for CVE-2026-42844
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install grav 2>/dev/null || \
sudo dnf upgrade grav 2>/dev/null || \
sudo yum update grav

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

# 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
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Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-42844 in getgrav grav?

Review vendor-specific security notices and update getgrav grav 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-2026-42844?

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-2026-42844?

CVE-2026-42844 is classified with a CVSS 3.1 Base Score of 8.8 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.8
HIGH SEVERITY
CVE ID CVE-2026-42844
Weakness CWE-269
Vendor getgrav
Product grav
Published 2026-05-12
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H