---
title: "CVE-2026-74225: U-Boot - Denial of Service"
description: "U-Boot before 2026.10-rc5 contains an out-of-bounds memory access caused by improper validation of SERVERID and CLIENTID option lengths in DHCPv6 packets, letting local network attackers corrupt memory and crash the bootloader during netboot."
url: https://panop.io/threat-heartbeat/CVE-2026-74225/
---

# CVE-2026-74225 U-Boot - Denial of Service

U-Boot before 2026.10-rc5 contains an out-of-bounds memory access caused by improper validation of SERVERID and CLIENTID option lengths in DHCPv6 packets, letting local network attackers corrupt memory and crash the bootloader during netboot.

CVSS base score 7.1 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.23% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-74225)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

29 September 2026

Updated

15 October 2026

Weakness

[CWE-787](https://cwe.mitre.org/data/definitions/787.html)

## Vendor fix

Update to version 2026.10-rc5 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-74225](https://nvd.nist.gov/vuln/detail/CVE-2026-74225)
- [https://github.com/u-boot/u-boot](https://github.com/u-boot/u-boot)
- [https://github.com/u-boot/u-boot/blob/v2026.07/net/dhcpv6.c#L304](https://github.com/u-boot/u-boot/blob/v2026.07/net/dhcpv6.c#L304)
- [https://github.com/u-boot/u-boot/commit/20209a62bc8565fc1e040882bc03c71ff0d73076](https://github.com/u-boot/u-boot/commit/20209a62bc8565fc1e040882bc03c71ff0d73076)
- [https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-out-of-bounds-write-via-dhcpv6](https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-out-of-bounds-write-via-dhcpv6)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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