HBOM vs SBOM: how hardware and software bills of materials differ
SBOMs and HBOMs share a purpose and increasingly a format, but they describe different things, come from different sources and change at different speeds.
- An SBOM inventories software components; an HBOM inventories physical components and their firmware.
- SBOM minimum elements come from NTIA (2021) and CISA’s 2026 update; HBOM guidance comes from CISA’s 2023 HBOM Framework and CERT-In.
- The CISA HBOM Framework places SBOM information explicitly out of scope, so the two must be linked deliberately.
- Firmware belongs to both, and CycloneDX and SPDX can express both in one document family.
Same idea, different object
A software bill of materials lists the components that make up a piece of software and their relationships; NTIA’s 2021 minimum elements set the baseline data fields, practices and automation expectations [1], and CISA and partner agencies published updated minimum elements in 2026 [2]. A hardware bill of materials applies the same principle to physical products: boards, chips, modules and the firmware on them. See What is an SBOM? and What is an HBOM? for the fundamentals.
Side-by-side comparison
| Dimension | SBOM | HBOM |
|---|---|---|
| Describes | Libraries, packages, applications, containers | Assemblies, components, chipsets, modules, firmware |
| Primary producer | Software developer or build pipeline | OEM and component suppliers |
| Typical identifiers | Package URL (purl), CPE, hashes | Manufacturer and supplier part numbers, serials, CPE hardware names [3] |
| Collection | Source, build or binary analysis | Supplier declaration plus device reporting |
| Rate of change | Every build or release | Firmware updates, part replacements, RMAs |
| Provenance focus | Repository, build system, maintainers | Manufacturer, factory, assembly and test locations [4] |
| Reference guidance | NTIA 2021; CISA 2026 minimum elements | CISA HBOM Framework 2023 |
| CERT-In v2.0 fields | 21 SBOM fields | Table 11 HBOM elements [5] |
| Can be verified against | Source code and builds | Device observations; physically only by inspection |
Different questions
An SBOM is most often used to answer: “Are we running the vulnerable version of this library?” An HBOM answers questions that have no software equivalent. Which products contain parts from a restricted entity? Which factories could a regional disruption affect? Which devices are past vendor support? The CISA framework groups these into compliance, security and availability use cases [4]. Availability in particular (single points of failure and supply clustering) is a hardware concern.
Different data sources
Software can be analysed directly: a build system knows what it compiled. Hardware can only be partly observed from outside. Management interfaces and OS tools report models, serials and firmware versions, but the sub-components inside a module, and where they were made, are known reliably only to the supplier. That is why HBOM programmes depend more on procurement clauses than SBOM programmes do (see HBOM procurement requirements).
The overlap: firmware
Firmware is software that ships inside hardware. The CISA HBOM Framework records basic firmware information but states that SBOM information is out of scope [4]. CERT-In’s HBOM guidance, by contrast, is read as extending to embedded software and firmware dependencies [6]. In practice, treat firmware as a component in the HBOM that points to its own SBOM. CycloneDX supports this with device and firmware component types in the same specification as software types [7]. Firmware BOMs covers this in more detail.
Different lifecycles
Software versions change weekly; hardware revisions may stay in service for a decade while firmware on them changes several times. An HBOM therefore needs to track two clocks at once: the long lifecycle of the physical part and the shorter lifecycle of its firmware.
Do you need both?
For software-only products, an SBOM may be enough. For appliances, servers, network equipment, IoT and OT devices, the vulnerability that matters may be in a controller’s firmware or a chipset, so SBOM alone leaves a blind spot. Organisations under CERT-In’s guidance will find that its SBOM and HBOM field lists overlap (name, version, supplier, licence, vulnerabilities, patch status, EOL date, hashes, unique identifier), which makes a shared data model practical [5]. Cryptography sits across both as well; a CBOM captures it.
How IntelliXBOM helps
IntelliXBOM handles SBOMs and HBOMs in CycloneDX and SPDX in one inventory, linking firmware components to their software contents. It correlates both with vulnerabilities, known-exploited lists, EOL data and business services, and validates each against its own required-field policy.
Frequently asked questions
Is an HBOM just an SBOM for hardware?
The concept is similar, but the data differs. An HBOM records manufacturers, part numbers, manufacturing locations and lifecycle dates for physical parts, which have no direct SBOM equivalent, while firmware links the two.
Can one CycloneDX file contain both hardware and software?
Yes. CycloneDX component types include device and firmware alongside application, library and operating system, so a single BOM can describe a device, its firmware and the software components within it.
Which should an organisation start with?
Most start with SBOMs because software changes faster and tooling is more mature. Organisations running critical appliances, network cores or OT should add HBOMs for those estates early, since vulnerabilities there are often in firmware.
Sources
- The Minimum Elements for a Software Bill of Materials (SBOM), July 2021NTIA, U.S. Department of Commercewww.ntia.gov/report/2021/minimum-elements-software-bill-materials-sbom
- 2026 Minimum Elements for a Software Bill of Materials (SBOM)CISA with NSA and partner agencieswww.cisa.gov/resources-tools/resources/2026-minimum-elements-software-bill-materials-sbom
- NIST IR 7695, Common Platform Enumeration: Naming Specification Version 2.3NISTcsrc.nist.gov/pubs/ir/7695/final
- A Hardware Bill of Materials (HBOM) Framework for Supply Chain Risk Management (September 2023)CISA ICT SCRM Task Forcewww.cisa.gov/sites/default/files/2023-09/A%20Hardware%20Bill%20of%20Materials%20Framework%20for%20Supply%20Chain%20Risk%20Management%20(508).pdf
- Technical Guidelines on SBOM, QBOM & CBOM, AIBOM and HBOM, Version 2.0 (9 July 2025)CERT-In, Government of Indiawww.cert-in.org.in/PDF/TechnicalGuidelines-on-SBOM,QBOM&CBOM,AIBOM_and_HBOM_ver2.0.pdf
- CERT-In’s New BOM Guidelines: What India’s Software, AI, and Hardware Ecosystem Needs to KnowAZB & Partnerswww.azbpartners.com/bank/cert-ins-new-bom-guidelines-what-indias-software-ai-and-hardware-ecosystem-needs-to-know/
- CycloneDX v1.6 JSON ReferenceOWASP CycloneDXcyclonedx.org/docs/1.6/json/
Sources checked in September 2026. Regulations and guidance change; always refer to the issuing body’s current publication. This content is for general information and is not legal advice.