AT91bootstrap before 3.9.2 does not properly wipe encryption and authentication keys from memory before passing control to a less privileged software component. This can be exploited to disclose these keys and subsequently encrypt and sign the next boot stage (such as the bootloader).

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-11684
• linux4sam/at91bootstrap@4541949
• https://labs.f-secure.com/advisories/microchip-at91bootstrap/