Das U-Boot before 2026.04 allows FIT (Flat Image Tree) signature verification bypass because hashed-nodes is omitted from a hash.

barebox is a bootloader. In barebox from version 2016.03.0 to before version 2026.03.1 (and the corresponding backport to 2025.09.3), an attacker could exploit a FIT signature verification vulnerability to trick the bootloader into booting different images than those that were verified as part of a signed configuration. mkimage(1) sets the hashed-nodes property of the FIT signature node to list which nodes of the FIT were hashed as part of the signing process as these will need to be verified later on by the bootloader. However, hashed-nodes itself is not part of the hash and could therefore be modified to allow booting different images than those that have been verified. This issue has been patched in barebox versions 2026.03.1 and backported to 2025.09.3.

An exploitable vulnerability exists in the verified boot protection of the Das U-Boot from version 2013.07-rc1 to 2014.07-rc2. The affected versions lack proper FIT signature enforcement, which allows an attacker to bypass U-Boot's verified boot and execute an unsigned kernel, embedded in a legacy image format. To trigger this vulnerability, a local attacker needs to be able to supply the image to boot.