CVE-2026-74225
HIGH 7.1U-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.
Severe if exploited (CVSS 7.1), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 14th percentile
Impact if exploited
7.1CVSS 4.0 · HIGH
- ConfidentialityNone
- IntegrityLow
- AvailabilityHigh
What an attacker needs
- ⚠Access: Must sit on the same / adjacent network
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Data snapshot:
Weakness (CWE)
- CWE-787: Out-of-bounds Write
CVSS vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
References and research data (JSON)
All CVSS metrics
- HIGH 7.1 v4.0 · CNA Primary
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N - HIGH 7.1 v3.1 · CNA Primary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H - HIGH 7.1 v4.0 · NVD Secondary
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - HIGH 7.1 v3.1 · NVD Secondary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
References
Patches & mitigations
- https://github.com/u-boot/u-boot/commit/20209a62bc8565fc1e040882bc03c71ff0d73076 CVE record · VulnCheck · Updated 2026-09-29T21:29:24.652Z
NVD · CVE-2026-74225 · Updated 2026-09-30T20:17:34.617
Advisories
- https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-out-of-bounds-write-via-dhcpv6 CVE record · VulnCheck · Updated 2026-09-29T21:29:24.652Z
NVD · CVE-2026-74225 · Updated 2026-09-30T20:17:34.617 - https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-89436 EUVD · EUVD-2026-89436
Technical & other
- https://github.com/u-boot/u-boot/blob/v2026.07/net/dhcpv6.c#L304 CVE record · VulnCheck · Updated 2026-09-29T21:29:24.652Z
NVD · CVE-2026-74225 · Updated 2026-09-30T20:17:34.617 - https://github.com/u-boot/u-boot CVE record · VulnCheck · Updated 2026-09-29T21:29:24.652Z
NVD · CVE-2026-74225 · Updated 2026-09-30T20:17:34.617