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

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% 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-195

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 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/nfs-common.c#L643
https://github.com/u-boot/u-boot/commit/1c0aff3a5fbfeee7a8948f624e0b8554e6e0d8fd
https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-buffer-overflow-via-nfs-readlink

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