CRITICAL CVSS 9.9
Published: 2026-05-19

CVE-2026-33642

kovidgoyal kitty Security Advisory (CVE-2026-33642)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-33642 impacting kovidgoyal kitty. Evaluated with CVSS Base Score of 9.9 (CRITICAL).

Original NVD Description

Source: NIST NVD
Kitty is a cross-platform GPU based terminal. In versions 0.46.2 and below, the handle_compose_command() function in kitty/graphics.c performs bounds validation on composition offsets using unsigned 32-bit arithmetic that is subject to integer wrapping, potentially leading to Heap Buffer Over-Read/Write. An attacker who can write escape sequences to a kitty terminal (e.g., via a malicious file, SSH login banner, or piped content) can supply crafted x_offset/y_offset values that pass the bounds check after wrapping but cause massive out-of-bounds heap memory access in compose_rectangles(). No user interaction is required. No non-default configuration is required. The attacker only needs the ability to produce output in a kitty terminal window. This issue has been fixed in version 0.47.0.

📊 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
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product kovidgoyal / kitty
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-2026-33642 impacting kovidgoyal kitty.

⚡ Nuclei Detection Template (YAML) cve-2026-33642.yaml
id: cve-2026-33642

info:
  name: kovidgoyal kitty - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-33642 affecting kovidgoyal kitty.
    Evaluation: Kitty is a cross-platform GPU based terminal. In versions 0.46.2 and below, the handle_compose_command() function in kitty/graphics.c performs bounds ...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-33642
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:H
    cvss-score: 9.9
    cve-id: CVE-2026-33642
    cwe-id: CWE-125
  tags: cve,cve-2026-33642,kovidgoyal,kitty,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "kitty"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-33642.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-33642
# Target: kovidgoyal kitty | CVSS: 9.9 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-33642 (kovidgoyal kitty)...")
    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 kovidgoyal kitty 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-2026-33642.sh
# Recommended Remediation & Patching Commands for CVE-2026-33642
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install kitty 2>/dev/null || \
sudo dnf upgrade kitty 2>/dev/null || \
sudo yum update kitty

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

# 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-2026-33642 in kovidgoyal kitty?

Review vendor-specific security notices and update kovidgoyal kitty 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-2026-33642?

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-2026-33642?

CVE-2026-33642 is classified with a CVSS 3.1 Base Score of 9.9 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.9
CRITICAL SEVERITY
CVE ID CVE-2026-33642
Weakness CWE-125
Vendor kovidgoyal
Product kitty
Published 2026-05-19
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:H