Boot image replacement via unsigned hashed-nodes property
Published May 16, 2026 · Updated May 16, 2026
Signature verification bypass in U-Boot before 2026.04 allows local users to boot attacker-selected code from a modified signed FIT. fit_config_check_sig trusts the unsigned hashed-nodes property to choose which FIT nodes are hashed, so an attacker can exclude a replaced image while preserving a valid signature. Exploitation requires read/write access to the FIT storage and signed-FIT secure boot; the payload runs with the original image's privileges, potentially compromising the kernel or higher firmware layers.
Summary
What happened
Signature verification bypass in U-Boot before 2026.04 allows local users to boot attacker-selected code from a modified signed FIT. fit_config_check_sig trusts the unsigned hashed-nodes property to choose which FIT nodes are hashed, so an attacker can exclude a replaced image while preserving a valid signature. Exploitation requires read/write access to the FIT storage and signed-FIT secure boot; the payload runs with the original image's privileges, potentially compromising the kernel or higher firmware layers.
The record
- CVE
- CVE-2026-46728
- Published
- May 16, 2026
- Updated
- May 16, 2026
- Vendor
- DENX Software Engineering GmbH
- Product
- U-Boot
- Classifications
- CWE-346, T1542.003
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- May 16, 2026CVE publishedPublication date reported by the CVE source.
- May 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <2026.04
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- U-Boot test_vboot forged FIT regression caseproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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