CVE-2026-74225: U-Boot before 2026.10-rc5 Out-of-Bounds Write via DHCPv6

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-29 · updated 2026-09-30
Weakness: CWE-787

Description

U-Boot before 2026.10-rc5 contains out-of-bounds memory access in dhcp6_parse_options() that fails to validate SERVERID and CLIENTID option lengths from DHCPv6 packets. Attackers on the local network can send crafted DHCPv6 ADVERTISE or REPLY packets during netboot to corrupt memory and crash the bootloader.

Affected products

u-boot: before 2026.10-rc5 — fixed in 2026.10-rc5

How to fix

Upgrade to a fixed version: u-boot 2026.10-rc5. Check the vendor advisory for mitigations.

References

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/commit/20209a62bc8565fc1e040882bc03c71ff0d73076
https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-out-of-bounds-write-via-dhcpv6

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