CVE-2025-11961
📋 TL;DR
CVE-2025-11961 is a heap-based buffer overflow vulnerability in libpcap's pcap_ether_aton() function. When applications pass malformed MAC address strings to this function, it can read beyond the string boundary and write beyond allocated buffers, potentially causing crashes or arbitrary code execution. This affects any application using vulnerable versions of libpcap for network packet capture and analysis.
💻 Affected Systems
- libpcap
- applications using libpcap (tcpdump, Wireshark, Nmap, network monitoring tools)
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full system compromise if an attacker can trigger the vulnerable function with controlled input through a network-facing service.
Likely Case
Application crashes (denial of service) when processing malformed network packets or configuration data containing invalid MAC addresses.
If Mitigated
Limited impact with proper input validation in calling applications or network segmentation isolating vulnerable systems.
🎯 Exploit Status
Exploitation requires the target application to call pcap_ether_aton() with attacker-controlled input. This is not a network-facing vulnerability by itself.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: libpcap with commit b2d2f9a9a0581c40780bde509f7cc715920f1c02
Vendor Advisory: https://github.com/the-tcpdump-group/libpcap/commit/b2d2f9a9a0581c40780bde509f7cc715920f1c02
Restart Required: Yes
Instructions:
1. Update libpcap from official repositories. 2. Rebuild any statically linked applications. 3. Restart affected services using libpcap.
🔧 Temporary Workarounds
Input validation in applications
allAdd strict MAC address format validation before calling pcap_ether_aton()
🧯 If You Can't Patch
- Avoid using pcap_ether_aton() function in applications
- Implement application-level MAC address validation using alternative methods
🔍 How to Verify
Check if Vulnerable:
Check libpcap version and compare with commit b2d2f9a9a0581c40780bde509f7cc715920f1c02 dateCheck Version:
pcap-config --version or check package manager (apt list libpcap, yum list libpcap, etc.)Verify Fix Applied:
Verify libpcap version includes the fix commit or is from after March 2025📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults when processing network data
- Unexpected memory access errors in libpcap-related processes
Network Indicators:
- Malformed packets containing invalid MAC address formats targeting libpcap applications
SIEM Query:
Process crashes with libpcap in stack trace OR network traffic containing malformed MAC addresses