CVE-2026-33243: barebox: FIT Signature Verification Bypass Vulnerability
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.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33243?
CVE-2026-33243 is classified as a high-severity vulnerability due to its potential to bypass signature verification in bootloader configurations.
How do I fix CVE-2026-33243?
To mitigate CVE-2026-33243, upgrade barebox to version 2025.09.3 or version 2026.03.1 or later.
Which versions of barebox are affected by CVE-2026-33243?
CVE-2026-33243 affects barebox versions from 2016.03.0 to before 2025.09.3, and from version 2025.10.0 to before 2026.03.1.
What is the impact of CVE-2026-33243?
The impact of CVE-2026-33243 is that an attacker could potentially forge a FIT image and bypass security mechanisms.
What component of barebox does CVE-2026-33243 affect?
CVE-2026-33243 specifically affects the FIT signature verification process within the barebox bootloader.