CRITICAL CVSS 9.1
Published: 2026-02-27

CVE-2026-28231

bigcat88 pillow-heif Security Advisory (CVE-2026-28231)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-28231 impacting bigcat88 pillow-heif. Evaluated with CVSS Base Score of 9.1 (CRITICAL).

Original NVD Description

Source: NIST NVD
pillow_heif is a Python library for working with HEIF images and plugin for Pillow. Prior to version 1.3.0, an integer overflow in the encode path buffer validation of `_pillow_heif.c` allows an attacker to bypass bounds checks by providing large image dimensions, resulting in a heap out-of-bounds read. This can lead to information disclosure (server heap memory leaking into encoded images) or denial of service (process crash). No special configuration is required — this triggers under default settings. Version 1.3.0 fixes the issue.

📊 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 bigcat88 / pillow-heif
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-2026-28231 impacting bigcat88 pillow-heif.

⚡ Nuclei Detection Template (YAML) cve-2026-28231.yaml
id: cve-2026-28231

info:
  name: bigcat88 pillow-heif - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-28231 affecting bigcat88 pillow-heif.
    Evaluation: pillow_heif is a Python library for working with HEIF images and plugin for Pillow. Prior to version 1.3.0, an integer overflow in the encode path buf...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-28231
  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-2026-28231
    cwe-id: CWE-125
  tags: cve,cve-2026-28231,bigcat88,pillow-heif,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "pillow-heif"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-28231.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-28231
# Target: bigcat88 pillow-heif | 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-2026-28231 (bigcat88 pillow-heif)...")
    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 bigcat88 pillow-heif 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-2026-28231.sh
# Recommended Remediation & Patching Commands for CVE-2026-28231
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install pillow-heif 2>/dev/null || \
sudo dnf upgrade pillow-heif 2>/dev/null || \
sudo yum update pillow-heif

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

# 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-2026-28231 in bigcat88 pillow-heif?

Review vendor-specific security notices and update bigcat88 pillow-heif 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-2026-28231?

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-2026-28231?

CVE-2026-28231 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-2026-28231
Weakness CWE-125
Vendor bigcat88
Product pillow-heif
Published 2026-02-27
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H