Eu Cyber Resilience Act Firmware Evidence Pack

title: "EU Cyber Resilience Act in Practice for Firmware Teams: Engineering Tasks and Evidence Pack" description: "Practical breakdown of the EU Cyber Resilience Act requirements for embedded firmware teams, covering technical obligations, SBOM requirements, vulnerability handling, and the evidence pack needed for compliance." date: 2026-04-19T08:00:00Z lastmod: 2026-04-19T08:00:00Z draft: false hero: "/images/hero/eu-cyber-resilience-act-firmware-evidence-pack-1600x900.jpg" tags:

• Embedded Linux
• ProteanOS
• Compliance category: dev

The EU Cyber Resilience Act (CRA) imposes cybersecurity requirements on products with digital elements sold in the European market. For embedded firmware teams, this is engineering work, not a compliance checkbox exercise. The regulation requires demonstrable security practices, documented vulnerability handling, and technical evidence that covers the full product lifecycle. This guide translates those obligations into concrete tasks.

What the CRA requires (simplified)

The CRA applies to products with digital elements, which includes essentially every connected embedded device. Requirements fall into three categories:

1. Security by design: The product must be designed with appropriate cybersecurity measures
2. Vulnerability handling: The manufacturer must have a process for handling vulnerabilities throughout the product's support period
3. Technical documentation: The manufacturer must maintain documentation demonstrating compliance

The support period is a minimum of 5 years from the product's market placement, or the expected product lifetime, whichever is longer.

Engineering tasks

Secure development lifecycle

The CRA expects a documented secure development process. For embedded firmware, that starts with threat modelling: identifying every attack surface (network interfaces, debug ports, update mechanisms, physical access) and documenting how each is addressed. It extends to secure coding practices - static analysis, structured code review, adherence to CERT C or MISRA standards where applicable - and to dependency management, which means tracking all third-party components with versions, licenses, and current vulnerability status.

The SLSA build provenance guide covers how to produce evidence that your build process is controlled and auditable.

SBOM generation

The CRA requires manufacturers to "identify and document vulnerabilities and components contained in the product, including by drawing up a software bill of materials."

This means generating an SBOM for every firmware release. The SBOM must include:

• All software components (open-source and proprietary)
• Component versions
• Licenses
• Dependency relationships
• Supplier information where applicable

The firmware SBOM guide covers SBOM generation in SPDX and CycloneDX formats.

Vulnerability handling

The CRA requires manufacturers to monitor continuously for vulnerabilities in their products, address them without delay, provide security updates free of charge, notify ENISA of actively exploited vulnerabilities within 24 hours of awareness, and inform users about the urgency of available updates.

The engineering implications are specific. You need automated CVE monitoring against your SBOM (Yocto's cve-check, Grype, or similar tools), an OTA update mechanism capable of deploying security patches - the OTA updates guide covers the technical options - VEX document generation to communicate "not affected" status and keep false positives from creating unnecessary noise, and an internal triage-to-release process with documented timelines.

Secure default configuration

Products must ship with secure defaults: no default passwords, unnecessary ports and services disabled, automatic security update mechanism enabled by default (or clearly user-configurable), data at rest encryption where warranted, and a minimal attack surface.

For embedded Linux, that translates to a minimal rootfs containing only required packages, firewall rules enabled from first boot, debug interfaces (UART, JTAG) disabled or authenticated in production builds, and the secure boot chain protecting firmware integrity end to end.

Logging and monitoring

Products must be able to "monitor and log their own security-relevant activity." For embedded devices this might include:

• Boot integrity status logging
• Authentication attempt logging
• Network connection logging
• Firmware update success/failure logging

Storage constraints on embedded devices make comprehensive logging challenging. Prioritize high-value events and consider log forwarding to a central server.

The evidence pack

The CRA requires maintaining technical documentation. Organise it as an "evidence pack" that covers:

1. Product description

• Hardware platform and SoC
• Software components and architecture diagram
• Network interfaces and protocols
• Update mechanism description

2. Risk assessment

• Threat model document
• Attack surface analysis
• Risk mitigation measures and their implementation evidence

3. SBOM

• Per-release SBOM in SPDX 3.0 or CycloneDX format
• Component version history across releases

4. Build evidence

• SLSA provenance documents for each release
• Build system description (Yocto version, toolchain, configuration)
• Reproducibility evidence (can you reproduce the build from the provenance?)

5. Vulnerability handling records

• CVE monitoring configuration and coverage
• Triage records for each relevant CVE
• VEX documents for "not affected" determinations
• Patch timeline records (time from CVE awareness to fix release)

6. Test evidence

• Security test results (SAST, DAST, fuzz testing)
• Penetration test reports (if applicable)
• Boot integrity test results
• Update mechanism test results

Timeline and categories

Product categories

The CRA defines three tiers:

• Default (Class I): Most products. Self-assessment is sufficient.
• Important (Class II): Products with higher risk (routers, firewalls, smart home hubs). Third-party assessment or conformity to harmonised standards.
• Critical: Very high risk (smart meters, industrial control). Third-party certification required.

Most embedded devices fall into Default or Important. Check the annexes for your product category.

Compliance timeline

• Vulnerability reporting obligation: September 2026
• Full compliance (all requirements): Late 2027

Start now. The vulnerability reporting obligation is less than a year away.

Integration with ProteanOS

ProteanOS's engineering practices align with CRA requirements:

• The packaging system generates SBOM-compatible metadata
• ProKit build outputs include component manifests
• The specifications section documents format standards that feed into technical documentation

For teams building on ProteanOS, the evidence pack is largely a matter of collecting artifacts that the build system already produces - SBOMs, provenance documents, VEX statements, and test results - into a structured compliance package.

Starting point

The EU CRA turns cybersecurity from a feature into a legal obligation. The vulnerability reporting requirement hits in September 2026, less than a year away. Start there: implement SBOM generation and automated CVE monitoring, then build the evidence pack structure around what your build system already produces. Most of the artifacts the CRA requires - SBOMs, provenance documents, VEX statements, test results - are outputs of a well-instrumented build pipeline. The compliance work is largely a matter of capturing them systematically, retaining them across releases, and structuring the documentation clearly enough that an auditor can follow it.