CVE-2026-24883
📋 TL;DR
This vulnerability in GnuPG allows an attacker to crash the application by sending a specially crafted signature packet with an excessive length. When parsed, this causes a NULL pointer dereference, resulting in denial of service. Anyone using vulnerable versions of GnuPG for encryption, decryption, or signature verification is affected.
💻 Affected Systems
- GnuPG (GPG)
📦 What is this software?
Gnupg by Gnupg
Gpg4win by Gpg4win
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for GnuPG-dependent applications, potentially disrupting encryption/decryption workflows, automated signing processes, or email security operations.
Likely Case
Application crash when processing malicious signatures, requiring manual restart of affected services or processes.
If Mitigated
Minimal impact with proper input validation and error handling in calling applications, though GnuPG itself would still crash.
🎯 Exploit Status
Exploitation requires the ability to provide a malicious signature to GnuPG, which could be achieved through various vectors including malicious files, emails, or API inputs.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.5.17 and later
Vendor Advisory: https://dev.gnupg.org/T8049
Restart Required: Yes
Instructions:
1. Download GnuPG 2.5.17 or later from https://gnupg.org/download. 2. Follow installation instructions for your platform. 3. Restart any services or applications using GnuPG.
🔧 Temporary Workarounds
Input validation wrapper
allImplement input validation in applications calling GnuPG to reject suspicious signature packets before passing to GnuPG.
🧯 If You Can't Patch
- Implement strict input validation in all applications that call GnuPG to filter potentially malicious signatures.
- Monitor GnuPG processes for crashes and implement automatic restart mechanisms for critical services.
🔍 How to Verify
Check if Vulnerable:
Run 'gpg --version' and check if version is below 2.5.17.Check Version:
gpg --version | head -1Verify Fix Applied:
After updating, run 'gpg --version' to confirm version is 2.5.17 or higher.📡 Detection & Monitoring
Log Indicators:
- GnuPG process crashes with segmentation fault or NULL pointer errors
- Application logs showing failed signature verification followed by service termination
Network Indicators:
- Unusual patterns of signature verification requests followed by service disruption
SIEM Query:
process_name:"gpg" AND (event_type:"crash" OR error:"segmentation fault" OR error:"NULL pointer")