U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK (CVE-2026-74221) | HOL Guard CVE

High · CVSS 8.8CVE-2026-74221

U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK

Answer in brief

CVE-2026-74221 records a High severity (CVSS 8.8) vulnerability in U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK. The current sources do not mark it as known exploited. The current feed maps u-boot/u-boot (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 29, 2026Updated Sep 29, 2026Source checked Sep 29, 2026First seen by HOL Sep 29, 2026Material review Sep 29, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps u-boot/u-boot (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
u-boot/u-bootgeneric	>=0 <2026.10-rc5	2026.10-rc5

Recommended response

Check inventory. Check lockfiles and deployed manifests for u-boot/u-boot.
Review the reported fix. Update u-boot/u-boot to 2026.10-rc5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 29, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.