CVE-2019-5478
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA weakness was found in Encrypt Only boot mode in Zynq UltraScale+ devices. This could lead to an adversary being able to modify the control fields of the boot image leading to an incorrect secure boot behavior.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA vulnerability in the Encrypt Only boot mode of Xilinx Zynq UltraScale+ devices allows modification of control fields in the boot image, potentially leading to incorrect or weakened secure boot behavior. An authenticated adversary with access to modify the encrypted boot image could exploit this to alter secure boot parameters.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Zynq UltraScale+ device modelLocate the device marking or query the device identification registers (e.g., via JTAG, U-Boot 'bdinfo', or Linux /sys/class/firmware/regulator). The affected models are Zu11eg, Zu15eg, Zu17eg, Zu19eg, Zu1cg, Zu1eg, Zu21dr, and Zu25dr.Affected if The device is any of the listed Zu* models with firmware that has not been patched.
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Determine the current boot mode configurationExamine the boot mode settings via the boot header, MODE pins, or boot ROM configuration registers. On Zynq UltraScale+, boot modes are set via the MODE pins (MIO pins 50-54) and verified in the boot header of the boot image.Affected if The device is configured to use 'Encrypt Only' boot mode, as opposed to authenticated encryption boot modes.
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Inspect the boot image configurationParse the boot image (BIN/BOOT.BIN) using Xilinx tools (e.g., Bootgen) or examine the boot header for the encryption and authentication settings. Look for fields indicating encryption without authentication.Affected if The boot image header shows encryption enabled but authentication disabled or not present.
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Verify secure boot enforcement in the PMU or boot ROMCheck the Platform Management Unit (PMU) firmware settings or secure boot configuration registers (e.g., via XSDB, Vivado, or the 'fw_printenv' / 'fw_setenv' utilities if secure boot is enabled).Affected if Secure boot is not enforcing authentication, or the configuration allows modification of control fields in the encrypted boot image.
If the device is an affected Zynq UltraScale+ model and is configured to use Encrypt Only boot mode without authentication, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate to vendor-provided firmware/patch addressing this weakness and review secure boot configuration settings. If no patch available, consider using authenticated encryption boot modes (e.g., encryption with authentication) rather than Encrypt Only mode.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2019-5478 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-5478 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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