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.

Published: 2026-03-20 Last update: 2026-03-26 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33243 is rated Low Risk (32.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33243

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-21 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33243

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.2 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.5 6.0 [email protected]

Weakness enumeration for CVE-2026-33243

OS Trackers for CVE-2026-33243

vendor priority summary link
alpine — CVE-2026-33243: 1 source package rows (u-boot); 61 state rows across 6 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 0, open 61. https://security.alpinelinux.org/vuln/CVE-2026-33243
debian not yet assigned CVE-2026-33243 not yet assigned priority: Debian including 1 source packages (u-boot), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2026-33243

Affected software / configurations for CVE-2026-33243

Vendor Product Version Raw CPE
denx u-boot >= 2013.07, < 2026.04 cpe:2.3:a:denx:u-boot:*:*:*:*:*:*:*:*
denx u-boot 2026.04 cpe:2.3:a:denx:u-boot:2026.04:rc1:*:*:*:*:*:*
denx u-boot 2026.04 cpe:2.3:a:denx:u-boot:2026.04:rc2:*:*:*:*:*:*
denx u-boot 2026.04 cpe:2.3:a:denx:u-boot:2026.04:rc3:*:*:*:*:*:*
pengutronix barebox >= 2016.03.0, < 2025.09.3 cpe:2.3:a:pengutronix:barebox:*:*:*:*:*:*:*:*
pengutronix barebox >= 2025.10.0, < 2026.03.1 cpe:2.3:a:pengutronix:barebox:*:*:*:*:*:*:*:*

References for CVE-2026-33243

cvelogic Threat Intelligence