CVE-2024-41928
📋 TL;DR
A buffer overflow vulnerability in bhyve's userspace process allows malicious software running in a guest virtual machine to execute arbitrary code on the host system. Since bhyve typically runs with root privileges, successful exploitation could lead to full host compromise. This affects FreeBSD systems using bhyve for virtualization.
💻 Affected Systems
- FreeBSD bhyve hypervisor
⚠️ 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
Full root-level compromise of the host system, allowing attacker persistence, data theft, and lateral movement to other systems.
Likely Case
Privilege escalation from guest VM to host root access, enabling complete control over the virtualization environment.
If Mitigated
Capsicum sandbox constraints limit the impact to capabilities available to the bhyve process, but root access still provides significant control.
🎯 Exploit Status
Requires attacker to first compromise a guest VM, then exploit the buffer overflow from within the VM to escape to the host.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FreeBSD 14.0-RELEASE p3, FreeBSD 13.3-RELEASE p3, FreeBSD 13.2-RELEASE p12
Vendor Advisory: https://security.freebsd.org/advisories/FreeBSD-SA-24:10.bhyve.asc
Restart Required: Yes
Instructions:
1. Update FreeBSD system using freebsd-update or pkg upgrade. 2. Apply the relevant patch release (p3 for 14.0/13.3, p12 for 13.2). 3. Reboot the system to ensure bhyve processes are restarted with patched code.
🔧 Temporary Workarounds
Disable bhyve
allTemporarily disable bhyve virtualization if not required
service bhyve stop
sysrc bhyve_enable="NO"
Isolate bhyve VMs
allEnsure bhyve guest VMs are isolated from untrusted networks and users
🧯 If You Can't Patch
- Isolate bhyve systems from production networks and sensitive data
- Implement strict access controls and monitoring for bhyve guest VMs
🔍 How to Verify
Check if Vulnerable:
Check FreeBSD version with 'uname -a' and verify if running affected versions (14.0 before p3, 13.3 before p3, 13.2 before p12)Check Version:
uname -a; freebsd-version -kruVerify Fix Applied:
Verify system is running patched version with 'freebsd-version -kru' and ensure all show patched version📡 Detection & Monitoring
Log Indicators:
- Unexpected bhyve process crashes
- Suspicious activity in bhyve logs
- Unauthorized privilege escalation attempts
Network Indicators:
- Unusual network traffic from bhyve host to internal systems
- Unexpected outbound connections from virtualization host
SIEM Query:
process_name:"bhyve" AND (event_type:"crash" OR privilege_escalation:true)