CVE-2024-29937 – This critical vulnerability in NFS implementati... (How to Fix)

Q: What is the severity of CVE-2024-29937?

CVE-2024-29937 has a CVSS score of 9.8 (CRITICAL). This critical vulnerability in NFS implementations allows remote attackers to execute arbitrary code on affected systems without requiring authentication. It affects OpenBSD and FreeBSD systems running vulnerable versions, potentially impacting any organization using these operating systems with NFS enabled.

📋 TL;DR

This critical vulnerability in NFS implementations allows remote attackers to execute arbitrary code on affected systems without requiring authentication. It affects OpenBSD and FreeBSD systems running vulnerable versions, potentially impacting any organization using these operating systems with NFS enabled.

💻 Affected Systems

Products:

OpenBSD
FreeBSD

Versions: OpenBSD through 7.4, FreeBSD through 14.0-RELEASE

Operating Systems: OpenBSD, FreeBSD

Default Config Vulnerable: ⚠️ Yes

Notes: Systems with NFS enabled are vulnerable. The bug is unrelated to memory corruption, suggesting a logic flaw in NFS protocol handling.

📦 What is this software?

Freebsd by Freebsd

View all CVEs affecting Freebsd →

Openbsd by Openbsd

View all CVEs affecting Openbsd →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise with root-level code execution, data exfiltration, and persistent backdoor installation across the network.

🟠

Likely Case

Remote code execution leading to data theft, lateral movement within the network, and potential ransomware deployment.

🟢

If Mitigated

Limited impact if NFS is disabled or properly firewalled, though other network services could still be at risk.

🌐 Internet-Facing: HIGH - Remote unauthenticated exploitation allows attackers to compromise systems directly from the internet.

🏢 Internal Only: HIGH - Even internally, this vulnerability can be exploited for lateral movement and privilege escalation.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

References indicate public discussion and technical details available. CVSS 9.8 suggests trivial exploitation with high impact.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check vendor advisories for specific patched versions

Vendor Advisory: https://www.openbsd.org/errata.html, https://www.freebsd.org/security/

Restart Required: Yes

Instructions:

1. Check current OS version. 2. Apply vendor patches via system update mechanisms. 3. Restart affected services or reboot system. 4. Verify patch application.

🔧 Temporary Workarounds

Disable NFS services

all

Completely disable NFS server and client services to eliminate attack surface

rcctl disable nfsd
rcctl disable mountd
rcctl disable statd
rcctl disable lockd

Network segmentation and firewall rules

all

Restrict NFS traffic to trusted networks only

pfctl -t nfs_trusted -T add 192.168.1.0/24
pass in proto tcp from <nfs_trusted> to port nfs

🧯 If You Can't Patch

Implement strict network segmentation to isolate NFS traffic
Deploy host-based intrusion detection and monitor for exploitation attempts

🔍 How to Verify

Check if Vulnerable:

Check OS version: uname -a for OpenBSD, freebsd-version for FreeBSD. Verify NFS services are running: sockstat -l | grep nfs

Check Version:

uname -a (OpenBSD) or freebsd-version (FreeBSD)

Verify Fix Applied:

Confirm OS version is patched and NFS services have been restarted. Test NFS functionality remains operational.

📡 Detection & Monitoring

Log Indicators:

Unusual NFS protocol errors
Unexpected process execution from NFS-related services
Authentication failures for NFS mounts

Network Indicators:

Abnormal NFS traffic patterns
NFS requests from unexpected sources
Protocol violations in NFS packets

SIEM Query:

source="*nfs*" AND (event_type="protocol_error" OR process_execution="unusual")

📊 Metadata

CVE ID: CVE-2024-29937

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-94

Published: April 11, 2024

Last Updated: June 17, 2025

🔗 References

https://news.ycombinator.com/item?id=39778203 Not Applicable
https://t2.fi/schedule/2024/ Not Applicable
https://www.signedness.org/t2.fi.2024/ Broken Link
https://www.youtube.com/watch?v=i_JOkHaCdzk Exploit
https://news.ycombinator.com/item?id=39778203 Not Applicable
https://t2.fi/schedule/2024/ Not Applicable
https://www.signedness.org/t2.fi.2024/ Broken Link
https://www.youtube.com/watch?v=i_JOkHaCdzk Exploit

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🔗 Related Vulnerabilities

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