Buffer overflow in U-Boot
CVE-2026-71971
U-Boot before 2026.10-rc3 with CONFIG_IP_DEFRAG enabled contains an out-of-bounds write vulnerability in the __net_defragment() function in net/net.c. Remote attackers can send a crafted IP fragment with non-zero offset and More-Fragments flag set during netboot to corrupt adjacent memory and crash the bootloader.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/u-boot/u-boot/commit/04ca915d5bf39dda5d1bce62d04d2b59d293c5b9 (patch)
- github.com/u-boot/u-boot/blob/v2026.07/net/net.c (technical-description)
- github.com/u-boot/u-boot (product)
- www.vulncheck.com/advisories/u-boot-before-2026.10-rc3-out-of-bounds-write-in-i… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-71971?
- CVE-2026-71971 is a high-severity vulnerability in U-Boot, classified under Out-of-bounds Write. CVSS score: 8.2/10. Published 2026-09-29.
- How severe is CVE-2026-71971?
- High severity. CVSS v3 base score is 8.2 out of 10.