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Vulnerability · Published Sep 29, 2026 · Assigned by VulnCheck

CVE-2026-74221U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK

High 8.2

In plain English

A high-severity security flaw 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 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.3%top 72.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

U-Boot before 2026.10-rc5 contains a buffer overflow in nfs_readlink_reply() function in net/nfs-common.c when processing NFS server responses. A malicious NFS server can send crafted READLINK replies with negative or oversized symlink length values to corrupt memory and crash the bootloader.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12u-bootno fix listedDEBIAN-CVE-2026-74221
Debian:13u-bootno fix listedDEBIAN-CVE-2026-74221
Debian:14u-bootno fix listedDEBIAN-CVE-2026-74221
Ubuntu:22.04:LTSu-boot2022.01+dfsg-2ubuntu2.9USN-8930-1
Ubuntu:22.04:LTSu-boot2022.01+dfsg-2ubuntu2.9UBUNTU-CVE-2026-74221
Ubuntu:24.04:LTSu-boot2025.10-0ubuntu0.24.04.4UBUNTU-CVE-2026-74221
Ubuntu:24.04:LTSu-boot2025.10-0ubuntu0.24.04.4USN-8930-1
Ubuntu:26.04:LTSu-boot2025.10-0ubuntu2.2UBUNTU-CVE-2026-74221
Ubuntu:26.04:LTSu-boot2025.10-0ubuntu2.2USN-8930-1
Ubuntu:26.10u-boot2025.10-0ubuntu6UBUNTU-CVE-2026-74221
Ubuntu:26.10u-boot2025.10-0ubuntu6USN-8930-2
Ubuntu:22.04:LTSu-boot-nezhano fix listedUBUNTU-CVE-2026-74221
Ubuntu:24.04:LTSu-boot-nezhano fix listedUBUNTU-CVE-2026-74221

Affected products (as reported)

VendorProductVersions
u-boot u-boot 0 – before 2026.10-rc5

Weakness: CWE-195 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

References