# CVE-2026-71974: U-Boot out-of-bounds write in read_slotted_partition()

Source: https://junglewise.ai/threats/cve-2026-71974-u-boot-before-2026-10-rc3-contains-an-out-of-bounds-write  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-29. Updated: 2026-09-29  
License: CC BY 4.0 with a link back

CVE-2026-71974 · Severity: medium · CVSS 4.8 · Published 2026-09-29

U-Boot is firmware that initializes hardware and loads the operating system on embedded devices and development boards. A flaw in how it reads boot images fails to check that image headers don't exceed the allocated buffer, allowing an attacker with physical access to a device to supply malicious boot media that overwrites bootloader memory and potentially executes arbitrary code.

Technologies: [U-Boot](https://junglewise.ai/threats/technologies/u-boot-u-boot). Vendors: [U-Boot](https://junglewise.ai/threats/vendors/u-boot).

## Quick answers

**Is CVE-2026-71974 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-71974 being exploited in the wild.

**How severe is CVE-2026-71974?** Medium severity, with a CVSS score of 4.8, published 29 September 2026.

**Which products and versions are affected?** U-Boot before 2026.10-rc3.

**Is there a fix for CVE-2026-71974?** 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-2026-71974 attacked?** It is attacked with physical access.

**Am I affected by CVE-2026-71974?** Check whether you run 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 read_slotted_partition() function in U-Boot's Android boot method lacks bounds validation on image size, permitting an out-of-bounds write when processing a crafted boot image with an oversized header. Physical access is required to supply malicious boot media; the vulnerability is most impactful on devices without Android Verified Boot (AVB) enabled. Attackers can overwrite bootloader memory to achieve code execution during the boot process.

## Affected products

- U-Boot U-Boot before 2026.10-rc3

## Timeline

- 2026-09-29: disclosed

## References

- [https://github.com/u-boot/u-boot](https://github.com/u-boot/u-boot)
- [https://github.com/u-boot/u-boot/blob/v2026.07/boot/bootmeth_android.c](https://github.com/u-boot/u-boot/blob/v2026.07/boot/bootmeth_android.c)

## Related threats

- [U-Boot use-after-free in lwIP wget HTTP callback](https://junglewise.ai/threats/cve-2026-74222-u-boot-before-2026-10-rc5-contains-a-use-after-free-vulnerability)
- [U-Boot out-of-bounds write in video_display_rle8_bitmap](https://junglewise.ai/threats/cve-2026-71972-u-boot-through-2026-10-rc5-contains-an-out-of-bounds-write)