CVE-2022-30767
📋 TL;DR
This vulnerability is a buffer overflow in Das U-Boot's NFS client implementation that allows remote code execution. It affects systems using U-Boot with NFS support enabled, particularly embedded devices and servers. The flaw exists due to an incorrect fix for a previous vulnerability (CVE-2019-14196).
💻 Affected Systems
- Das U-Boot
📦 What is this software?
Fedora by Fedoraproject
⚠️ Risk & Real-World Impact
Worst Case
Remote attacker gains full control of affected device, potentially compromising the entire system and network.
Likely Case
Remote code execution leading to device compromise, data theft, or persistence installation.
If Mitigated
Limited impact if NFS is disabled or proper network segmentation is in place.
🎯 Exploit Status
Exploit details and proof-of-concept are publicly available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit bdbf7a05e26f3c5fd437c99e2755ffde186ddc80 and later
Vendor Advisory: https://lists.denx.de/pipermail/u-boot/2022-May/483952.html
Restart Required: Yes
Instructions:
1. Update U-Boot to version with commit bdbf7a05e26f3c5fd437c99e2755ffde186ddc80 or later. 2. Rebuild U-Boot with updated source. 3. Flash updated U-Boot to affected devices. 4. Reboot devices.
🔧 Temporary Workarounds
Disable NFS support
allDisable NFS client functionality in U-Boot configuration
# In U-Boot configuration, set CONFIG_CMD_NFS=n
Network segmentation
allRestrict NFS access to trusted networks only
🧯 If You Can't Patch
- Disable NFS functionality in U-Boot configuration
- Implement strict network segmentation and firewall rules to block NFS traffic
🔍 How to Verify
Check if Vulnerable:
Check U-Boot version and configuration for NFS support. Vulnerable if version ≤ 2022.04 or ≤ 2022.07-rc2 with NFS enabled.Check Version:
printenv version # in U-Boot console, or check bootloader version during system startupVerify Fix Applied:
Verify U-Boot version includes commit bdbf7a05e26f3c5fd437c99e2755ffde186ddc80 and NFS functionality still works properly.📡 Detection & Monitoring
Log Indicators:
- Unexpected NFS connection attempts
- U-Boot crash logs
- Memory corruption errors
Network Indicators:
- Suspicious NFS traffic to U-Boot devices
- Unexpected NFS protocol anomalies
SIEM Query:
source="*nfs*" AND (event="buffer_overflow" OR event="memory_corruption")🔗 References
- https://github.com/u-boot/u-boot/commit/5d14ee4e53a81055d34ba280cb8fd90330f22a96
- https://lists.denx.de/pipermail/u-boot/2022-May/483952.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DF62MVMH3QUGMBDCB3DY2ERQ6EBHTADB/
- https://securitylab.github.com/research/uboot-rce-nfs-vulnerability/
- https://source.denx.de/u-boot/u-boot/-/commit/bdbf7a05e26f3c5fd437c99e2755ffde186ddc80
- https://github.com/u-boot/u-boot/commit/5d14ee4e53a81055d34ba280cb8fd90330f22a96
- https://lists.debian.org/debian-lts-announce/2025/05/msg00001.html
- https://lists.denx.de/pipermail/u-boot/2022-May/483952.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DF62MVMH3QUGMBDCB3DY2ERQ6EBHTADB/
- https://securitylab.github.com/research/uboot-rce-nfs-vulnerability/
- https://source.denx.de/u-boot/u-boot/-/commit/bdbf7a05e26f3c5fd437c99e2755ffde186ddc80
