Is CVE-2026-74221 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-74221 being exploited in the wild.

How severe is CVE-2026-74221?

High severity, with a CVSS score of 8.2, published 29 September 2026.

Which products and versions are affected?

Das U-Boot U-Boot before 2026.10-rc5.

Is there a fix for CVE-2026-74221?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-74221 attacked?

It is attacked over the network, in device firmware.

Am I affected by CVE-2026-74221?

Check whether you run Das U-Boot U-Boot at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-74221: U-Boot buffer overflow in nfs_readlink_reply

CVE-2026-74221 · Severity: high · CVSS 8.2 · Published 2026-09-29

U-Boot is firmware that boots embedded systems and devices before the main operating system loads. A buffer overflow vulnerability in its NFS network file access code allows a malicious NFS server to send specially crafted responses that crash the bootloader or potentially corrupt firmware. An attacker on the network segment with access to NFS communication could exploit this during device boot.

Technologies: Das U-Boot U-Boot. Vendors: Das U-Boot.

Quick answers

Is CVE-2026-74221 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-74221 being exploited in the wild.
How severe is CVE-2026-74221?: High severity, with a CVSS score of 8.2, published 29 September 2026.
Which products and versions are affected?: Das U-Boot U-Boot before 2026.10-rc5.
Is there a fix for CVE-2026-74221?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-74221 attacked?: It is attacked over the network, in device firmware.
Am I affected by CVE-2026-74221?: Check whether you run Das U-Boot U-Boot at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The nfs_readlink_reply() function in net/nfs-common.c fails to properly validate symlink length values in NFS READLINK responses, permitting negative or oversized values to trigger a buffer overflow. The vulnerability requires network access to intercept or control NFS server responses during boot. Exploitation leads to memory corruption and denial of service; a fix is available in U-Boot 2026.10-rc5 and later.

Affected products

Das U-Boot U-Boot before 2026.10-rc5

Timeline

2026-09-29: disclosed

References

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