Buffer Overflow Vulnerability in U-Boot Bootloader
CVE-2026-74221

8.8HIGH

Key Information:

Vendor

U-boot

Status
U-boot
Vendor
CVE Published:
29 September 2026

What is CVE-2026-74221?

The U-Boot bootloader, prior to version 2026.10-rc5, is susceptible to a buffer overflow vulnerability within the nfs_readlink_reply() function located in net/nfs-common.c. This flaw arises when the bootloader processes crafted READLINK replies from a malicious NFS server that contain negative or oversized symlink length values. Such responses can lead to memory corruption, which may ultimately crash the bootloader, affecting the integrity and stability of the system it operates on.

Affected Version(s)

u-boot 0 < 2026.10-rc5

References

https://github.com/u-boot/u-boot/commit/1c0aff3a5fbfeee7a...
patch
https://github.com/u-boot/u-boot/blob/v2026.07/net/nfs-co...
technical-description
https://github.com/u-boot/u-boot
product

CVSS V4

Score:
8.8
Severity:
HIGH
Confidentiality:
None
Integrity:
Low
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Shahriyar Jalayeri (ByteRay Ltd.)
Mehrun P. Hunter (ByteRay Ltd.)
.