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Vulnerability · Published Sep 29, 2026 · Assigned by VulnCheck

CVE-2026-71971U-Boot before 2026.10-rc3 Out-of-Bounds Write in IP Fragment Reassembly

High 8.2

In plain English

A high-severity out-of-bounds write in u-boot from u-boot. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.4%top 68.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12u-bootno fix listedDEBIAN-CVE-2026-71971
Debian:13u-bootno fix listedDEBIAN-CVE-2026-71971
Debian:14u-bootno fix listedDEBIAN-CVE-2026-71971
Ubuntu:22.04:LTSu-boot2022.01+dfsg-2ubuntu2.8USN-8884-1
Ubuntu:22.04:LTSu-boot2022.01+dfsg-2ubuntu2.8UBUNTU-CVE-2026-71971
Ubuntu:24.04:LTSu-boot2025.10-0ubuntu0.24.04.3USN-8884-1
Ubuntu:24.04:LTSu-boot2025.10-0ubuntu0.24.04.3UBUNTU-CVE-2026-71971
Ubuntu:26.04:LTSu-boot2025.10-0ubuntu2.1USN-8884-1
Ubuntu:26.04:LTSu-boot2025.10-0ubuntu2.1UBUNTU-CVE-2026-71971
Ubuntu:26.10u-boot2025.10-0ubuntu5UBUNTU-CVE-2026-71971
Ubuntu:22.04:LTSu-boot-nezhano fix listedUBUNTU-CVE-2026-71971
Ubuntu:24.04:LTSu-boot-nezhano fix listedUBUNTU-CVE-2026-71971

Affected products (as reported)

VendorProductVersions
u-boot u-boot 0 – before 2026.10-rc3

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

References