Is CVE-2026-71971 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-71971 being exploited in the wild.

How severe is CVE-2026-71971?

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-rc3 with CONFIG_IP_DEFRAG enabled.

Is there a fix for CVE-2026-71971?

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-2026-71971 attacked?

It is attacked over the network, in device firmware.

Am I affected by CVE-2026-71971?

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-2026-71971: U-Boot out-of-bounds write in IP defragmentation

CVE-2026-71971 · Severity: high · CVSS 8.2 · Published 2026-09-29

U-Boot is a bootloader that initializes embedded systems and loads the operating system. During network boot operations, a remote attacker can send a specially crafted IP packet fragment to trigger an out-of-bounds write in the defragmentation logic, corrupting memory and crashing the device before it boots. This affects devices using U-Boot with IP defragmentation enabled, blocking legitimate boot operations.

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

Quick answers

Is CVE-2026-71971 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-71971 being exploited in the wild.
How severe is CVE-2026-71971?: 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-rc3 with CONFIG_IP_DEFRAG enabled.
Is there a fix for CVE-2026-71971?: 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-2026-71971 attacked?: It is attacked over the network, in device firmware.
Am I affected by CVE-2026-71971?: 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 vulnerability is an out-of-bounds write in the __net_defragment() function in net/net.c, triggered when processing IP fragments with a non-zero offset and the More-Fragments flag set. An unauthenticated remote attacker on the network can send a malicious fragment during netboot to write beyond allocated buffer boundaries, corrupting adjacent memory and causing a crash. A patch is available in U-Boot 2026.10-rc3 and later.

Affected products

Das U-Boot U-Boot before 2026.10-rc3 with CONFIG_IP_DEFRAG enabled

Timeline

2026-09-29: disclosed

References

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