CVE-2026-33243
Pengutronix Barebox 2016.03.0 – 2025.09.3
Raw vector
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-33243 is a high-severity Insufficient Verification of Data Authenticity (CWE-345) vulnerability in Pengutronix Barebox. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Component Firmware (T1542.002); ranked at the 1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-23 (Session Authenticity) and SI-7 (Software, Firmware, and Information Integrity) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33243 affects the barebox bootloader, a component used in embedded systems for initial boot processes. The vulnerability resides in the Flattened Image Tree (FIT) signature verification mechanism, present in barebox versions from 2016.03.0 up to but not including 2026.03.1, with a corresponding backport issue fixed in 2025.09.3. Specifically, the mkimage tool sets a hashed-nodes property in the FIT signature node to specify which nodes were hashed during signing for later verification by the bootloader. However, this hashed-nodes property itself is excluded from the hash computation, enabling post-signing modifications (classified under CWE-345: Insufficient Verification of Data Authenticity).
Exploitation requires local access (AV:L) with high privileges (PR:H), low attack complexity (AC:L), and no user interaction (UI:N). A privileged local attacker can alter the hashed-nodes property in a signed FIT configuration to reference different images than those originally verified. This tricks the bootloader into accepting and executing unauthorized images during boot, potentially leading to arbitrary code execution with high impacts on confidentiality, integrity, availability (C:H/I:H/A:H), and changed scope (S:C), as reflected in the CVSS v3.1 base score of 8.2.
Mitigation is available through patches in barebox version 2026.03.1 and the backport to 2025.09.3. Security practitioners should update affected systems immediately. Detailed patch information is in the commit at https://github.com/barebox/barebox/commit/aca01795056d51060cb096f9a1ea309361743e05, and further guidance is provided in the GitHub Security Advisory at https://github.com/barebox/barebox/security/advisories/GHSA-3fvj-q26p-j6h4.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-13893
Vulnerability Data
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…
more
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
- 8 hardening rules · 5 OS baselines
V3.5.5
Mitigating Controls (NIST 800-53 r5) AI
Explicit requirement to protect session authenticity structurally prevents the weakness for communications.
Integrity verification tools detect (but do not stop) the acceptance of data lacking authenticity.
Cryptographic mechanisms can be used to verify authenticity, thereby preventing acceptance of invalid data.
Associating security attributes with exchanged information supports verification of authenticity.
Integrity protection on transmitted data directly stops acceptance of unauthenticated or altered data.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
CWE-345 directly impairs RC.RP-05's verification of restored-asset integrity/authenticity, largely defeating the outcome while still leaving other restoration-confirmation steps partially viable.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Network controls can enforce authenticated channels, reducing risk of accepting unauthentic data.
Secure network services often include authenticity checks for data exchanged over those services.
Cryptographic mechanisms directly verify data origin and integrity, preventing acceptance of unauthentic data.
Secure SDLC incorporates authenticity verification requirements throughout development.
Application security requirements can mandate data authenticity verification mechanisms.
Secure coding practices include implementing proper data authenticity checks.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-345
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
Oracle Linux 9 (1 rule)
- V-271525 OL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-345
RHEL 7 (2 rules)
- V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
- V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
RHEL 8 (2 rules)
- V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
- V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
RHEL 9 (1 rule)
- V-257822 RHEL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-345