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CVE-2026-33243

HIGHCVSS 8.2/10EPSS 0.11%

Last modified

CVE-2026-33243 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. 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. EPSS estimates a 0.11% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
8.2/10

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS Probability
0.11%

1.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
DenxU-Boot>= 2013.07, < 2026.04—
DenxU-Boot2026.04Rc1
PengutronixBarebox>= 2016.03.0, < 2025.09.3—
PengutronixBarebox>= 2025.10.0, < 2026.03.1—

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-33243?
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.
How severe is CVE-2026-33243?
CVE-2026-33243 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.11% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33243?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33243?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST