CRITICAL CVSS 9.1
Published: 2026-05-07

CVE-2026-42216

openexr openexr Security Advisory (CVE-2026-42216)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-42216 impacting openexr openexr. Evaluated with CVSS Base Score of 9.1 (CRITICAL).

Original NVD Description

Source: NIST NVD
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From versions 3.0.0 to before 3.2.9, 3.3.0 to before 3.3.11, and 3.4.0 to before 3.4.11, IDManifest::init() reconstructs strings from a prefix-compressed representation. If the previous string is longer than 255 bytes, the next string is expected to begin with a 2-byte prefix length. The code reads stringList[i][0] and stringList[i][1] without checking that the current string has at least two bytes. This issue has been patched in versions 3.2.9, 3.3.11, and 3.4.11.

📊 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
None (I:N)
No system modification impact
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product openexr / openexr
Affected Versions *
Weakness Enumeration CWE-125

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-2026-42216 impacting openexr openexr.

⚡ Nuclei Detection Template (YAML) cve-2026-42216.yaml
id: cve-2026-42216

info:
  name: openexr openexr - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-42216 affecting openexr openexr.
    Evaluation: OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From ...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-42216
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
    cvss-score: 9.1
    cve-id: CVE-2026-42216
    cwe-id: CWE-125
  tags: cve,cve-2026-42216,openexr,openexr,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "openexr"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-42216.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-42216
# Target: openexr openexr | CVSS: 9.1 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-42216 (openexr openexr)...")
    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 openexr openexr 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-2026-42216.sh
# Recommended Remediation & Patching Commands for CVE-2026-42216
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install openexr 2>/dev/null || \
sudo dnf upgrade openexr 2>/dev/null || \
sudo yum update openexr

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

# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-42216 in openexr openexr?

Review vendor-specific security notices and update openexr openexr 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-2026-42216?

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-2026-42216?

CVE-2026-42216 is classified with a CVSS 3.1 Base Score of 9.1 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.1
CRITICAL SEVERITY
CVE ID CVE-2026-42216
Weakness CWE-125
Vendor openexr
Product openexr
Published 2026-05-07
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H