CVE-2025-6966
📋 TL;DR
A NULL pointer dereference vulnerability in python-apt's TagSection.keys() function allows local attackers to crash processes by providing malformed deb822 files with non-UTF-8 keys. This affects APT-based Linux systems like Ubuntu and Debian where python-apt is used for package management operations. The vulnerability requires local access to the system.
💻 Affected Systems
- python-apt
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Persistent denial of service affecting package management operations, potentially disrupting system updates and software installation processes.
Likely Case
Temporary process crash of python-apt related operations when processing malicious deb822 files, requiring manual restart of affected processes.
If Mitigated
Minimal impact with proper file access controls preventing unauthorized users from placing malicious deb822 files in sensitive locations.
🎯 Exploit Status
Exploitation requires local access and ability to create or modify deb822 files that python-apt processes. No authentication bypass is needed beyond local file creation permissions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: python-apt 2.9.2 and later
Vendor Advisory: https://lists.debian.org/debian-lts-announce/2025/12/msg00019.html
Restart Required: No
Instructions:
1. Update package lists: sudo apt update
2. Upgrade python-apt: sudo apt install --only-upgrade python-apt
3. Verify installation: apt-cache policy python-apt
🔧 Temporary Workarounds
Restrict deb822 file access
linuxLimit write access to directories containing deb822 files that python-apt processes
sudo chmod 644 /etc/apt/sources.list.d/*.list
sudo chown root:root /etc/apt/sources.list.d/*.list
🧯 If You Can't Patch
- Implement strict file permissions on /etc/apt/sources.list.d/ and other deb822 file locations
- Monitor for unexpected process crashes of python-apt related operations and investigate source
🔍 How to Verify
Check if Vulnerable:
Check python-apt version: dpkg -l python-apt | grep ^iiCheck Version:
dpkg -l python-apt | grep ^ii | awk '{print $3}'Verify Fix Applied:
Verify installed version is 2.9.2 or higher: apt-cache policy python-apt📡 Detection & Monitoring
Log Indicators:
- Segmentation fault or crash logs from python-apt processes
- Unexpected termination of apt or dpkg operations
Network Indicators:
- None - local vulnerability only
SIEM Query:
process.name:python AND event.action:crash AND process.args:*apt*