Out-of-Bounds Write Vulnerability in U-Boot Bootloader
CVE-2026-71971

8.8HIGH

Key Information:

Vendor

U-boot

Status
U-boot
Vendor
CVE Published:
29 September 2026

What is CVE-2026-71971?

A vulnerability exists in U-Boot bootloader versions prior to 2026.10-rc3, specifically within the __net_defragment() function in net/net.c. This flaw arises when CONFIG_IP_DEFRAG is enabled. Remote attackers can exploit this vulnerability by sending a specially crafted IP fragment with a non-zero offset and the More-Fragments flag during netboot. Successful exploitation allows attackers to overwrite adjacent memory, potentially leading to system crashes and instability.

Affected Version(s)

u-boot 0 < 2026.10-rc3

References

https://github.com/u-boot/u-boot/commit/04ca915d5bf39dda5...
patch
https://github.com/u-boot/u-boot/blob/v2026.07/net/net.c#...
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.)
.