CVE-2026-29009: U-Boot NFS Client Buffer Overflow via Malicious NFS Server

Summary

A security flaw in U-Boot's NFS client allows a malicious NFS server to corrupt U-Boot's memory, potentially taking control of the system. This vulnerability affects U-Boot versions up to 2026.04-rc3 when the NFS feature is enabled. To fix this issue, update to the latest version of U-Boot or disable the NFS feature if it's not needed.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software

Vendor	Product	Affected versions
u-boot	u-boot	<= 2026.04-rc3
denx	u-boot	< 2026.04 2026.04 `cpe:2.3:a:denx:u-boot::::::::`

Original title

U-Boot through 2026.04-rc3 contains a buffer overflow vulnerability in nfs_readlink_reply() (net/nfs-common.c) when CONFIG_CMD_NFS is enabled, allowing a malicious or compromised NFS server to over...

Original description

U-Boot through 2026.04-rc3 contains a buffer overflow vulnerability in nfs_readlink_reply() (net/nfs-common.c) when CONFIG_CMD_NFS is enabled, allowing a malicious or compromised NFS server to overflow the 2048-byte nfs_path_buff buffer by returning multiple relative symlink targets that are appended without cumulative length validation. Attackers can send two or more READLINK responses containing relative symlink targets of approximately 1100 bytes each to corrupt adjacent BSS variables including nfs_server_ip, nfs_server_mount_port, nfs_server_port, nfs_our_port, nfs_state, and rpc_id, potentially achieving memory corruption and control over the NFS client state machine.

mitre CVSS3.1 8.2

Vulnerability type

CWE-120 Classic Buffer Overflow

https://lists.denx.de/pipermail/u-boot/2026-May/617853.html issue-tracking
https://u-boot.org/ product
https://www.vulncheck.com/advisories/u-boot-rc3-buffer-overflow-in-nfs-readlink-... third-party-advisory
https://y637f9qq2x.com/posts/u-boot-tcp-nfs-vulns/ technical-description exploit