MEDIUM CVSS 5.9
Published: 2026-04-06

CVE-2026-34380

openexr openexr Security Advisory (CVE-2026-34380)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-34380?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-34380 impacting openexr openexr. Evaluated with CVSS Base Score of 5.9 (MEDIUM).

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 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
High (AC:H)
Depends on race conditions or environment
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
Required (UI:R)
User must click or open resource
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
Low (I:L)
Partial data modification possible
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product openexr / openexr
Affected Versions *
Weakness Enumeration CWE-190

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-2026-34380 impacting openexr openexr.

⚡ Nuclei Detection Template (YAML) cve-2026-34380.yaml
id: cve-2026-34380

info:
  name: openexr openexr - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-34380 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-2026-34380
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
    cvss-score: 5.9
    cve-id: CVE-2026-34380
    cwe-id: CWE-190
  tags: cve,cve-2026-34380,openexr,openexr,medium

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-2026-34380.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-34380
# Target: openexr openexr | CVSS: 5.9 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-34380 (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-2026-34380.sh
# Recommended Remediation & Patching Commands for CVE-2026-34380
# 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-2026-34380 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-2026-34380?

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-2026-34380?

CVE-2026-34380 is classified with a CVSS 3.1 Base Score of 5.9 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.9
MEDIUM SEVERITY
CVE ID CVE-2026-34380
Weakness CWE-190
Vendor openexr
Product openexr
Published 2026-04-06
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H