Using SBOMs to Govern Cross-Compilation, Cross-Architecture, and Multi-Target Build Outputs in Federal Software Pipelines

Federal software pipelines have grown considerably more complex over the past decade. Programs that once built a single Linux binary now produce artifacts for multiple processor architectures, operating systems, container runtimes, and embedded targets, often from a shared codebase and a single CI/CD pipeline. That shift creates a category of build risk that standard SBOM practices were not designed to address: the risk that two binaries compiled from identical source code carry materially different dependency graphs, native libraries, and compiler behaviors depending on the target platform.

Cross-compilation SBOM governance is the discipline of ensuring that each target-specific artifact produced by a multi-target build pipeline is accompanied by an SBOM that accurately reflects what was actually compiled into that binary, not what the source repository declares in aggregate. The distinction matters operationally. A vulnerability in a native library may affect the ARM64 build of an application but not the x86_64 build, because the two targets resolved different platform-specific packages during dependency resolution. Without target-aware SBOMs, that difference is invisible to assessors, ISSOs, and mission owners.

DoD programs operating edge systems, embedded platforms, and mixed-architecture endpoint fleets face this problem acutely. So do civilian agencies managing cloud-native workloads alongside on-premises infrastructure where the same application image may be deployed to x86 servers, ARM-based cloud instances, or Windows endpoints. The SBOM that satisfies an assessor reviewing the cloud deployment may not accurately represent the binary running on the edge device.

This article addresses how federal teams should structure SBOM workflows for multi-target builds, what metadata must be preserved to support traceability, how to detect mismatches between declared build inputs and delivered artifacts, and how to support assurance reviews across heterogeneous build environments. It assumes the reader is already familiar with SBOM formats and federal SBOM requirements and focuses specifically on the complexity introduced by architecture variance and conditional compilation.

Why Target Variance Breaks Aggregate SBOMs

Most SBOM generation tools operate at the source or manifest level. They read a package manifest, a lock file, or a dependency graph declared in the repository and produce a document that lists what the project depends on. That approach works reasonably well when a project produces a single artifact for a single target. It breaks down when the same source base produces multiple binaries for different platforms, because the dependency graph that actually gets compiled into each binary is not the same as the aggregate dependency graph declared in the manifest.

Package managers resolve dependencies differently depending on the target platform. A Rust project using conditional compilation with cfg attributes may pull in entirely different crates on Windows versus Linux. A Python package with C extensions may resolve to different pre-compiled wheels depending on the processor architecture. A Go project cross-compiled for Linux/ARM64 may link against different system libraries than the same project compiled natively for Linux/x86_64. In each case, the source-level manifest looks identical, but the compiled artifact carries a materially different dependency set.

The operational consequence is that a vulnerability scan run against an aggregate SBOM may produce false negatives for specific target platforms. An assessor reviewing a single SBOM for a multi-target application cannot determine which vulnerabilities apply to which deployed artifact without target-specific data. For programs operating across mixed-architecture fleets, that gap is not a documentation problem. It is a mission risk that affects patching decisions, authorization boundaries, and incident response.

Federal programs that have adopted the Software Bill of Materials (SBOM) as a supply chain risk management tool need to extend that practice to cover target-specific outputs if they operate multi-target pipelines. An SBOM that does not reflect the actual binary delivered to a specific platform provides incomplete assurance regardless of how well it was generated.

Modeling Build Outputs as Distinct SBOM Subjects

The foundational design decision for multi-target SBOM governance is to treat each build output as a distinct SBOM subject rather than a variant of a shared document. That means each combination of operating system, processor architecture, build profile, and deployment target gets its own SBOM, linked to the specific binary it describes.

In practice, a program that builds a single application for Linux/x86_64, Linux/ARM64, and Windows/x86_64 should produce three separate SBOMs. Each document should identify the target platform explicitly in its metadata, reference the artifact digest of the binary it describes, and list only the dependencies that were actually resolved and compiled for that target. Shared source-level dependencies may appear in all three documents, but platform-specific packages, native extensions, and architecture-dependent libraries should appear only in the documents for the targets that include them.

This model requires a naming and identification convention that allows downstream consumers to query SBOMs by target. A simple approach is to encode the target triple or platform identifier in the SBOM document name and in the primary component metadata. More structured approaches use SBOM relationships to link a parent document representing the source component to child documents representing each target artifact. Either approach is workable, but the convention must be documented and consistently applied across the pipeline so that assessors, ISSOs, and automated scanners can reliably retrieve the correct SBOM for a given deployed binary.

The table below illustrates how a single codebase producing three target artifacts should be modeled as distinct SBOM subjects, with the key metadata fields that differentiate each document.

Target	SBOM Subject	Artifact Digest	Target-Specific Dependencies	Toolchain Captured
Linux/x86_64	app-linux-amd64 v2.4.1	sha256 of produced binary	glibc, x86 native extensions	Required
Linux/ARM64	app-linux-arm64 v2.4.1	sha256 of produced binary	glibc, ARM64 native extensions, cross-compiler sysroot libs	Required
Windows/x86_64	app-windows-amd64 v2.4.1	sha256 of produced binary	MSVC runtime, Windows-specific packages, WinAPI bindings	Required

Capturing Toolchains, Native Libraries, and Conditional Compilation Paths

Runtime dependencies are the most visible part of an SBOM, but for cross-compiled and multi-target builds, the toolchain is equally important. The compiler version, linker, cross-compilation toolchain, sysroot, and any build-time code generators all affect what ends up in the binary. A vulnerability in a cross-compiler or a sysroot library is a supply chain risk that a runtime-only SBOM will not capture.

Federal programs should treat the toolchain as a first-class SBOM subject for each target build. That means recording the compiler name and version, the target triple it was configured for, the sysroot path and version when cross-compiling, and any build-time tools that generate code or link additional libraries. This information belongs in the SBOM as a build-time dependency relationship, not in a separate document that may not be retained alongside the artifact.

Conditional Compilation and Feature Flags

Conditional compilation is one of the most common sources of dependency divergence in multi-target builds. When a codebase uses preprocessor directives, build feature flags, or language-level conditional compilation to include or exclude code paths based on the target platform, the resulting binaries may have entirely different dependency graphs even though they were compiled from the same source files.

The SBOM for each target must reflect the feature flags and compilation conditions that were active during that specific build. A build that enables a hardware acceleration library on x86_64 but falls back to a software implementation on ARM64 should produce two SBOMs with different dependency entries, not a single SBOM that lists both libraries as optional. Listing both as optional in a shared document obscures which binary actually carries the dependency and makes vulnerability correlation unreliable.

Capturing this accurately requires that the pipeline record the exact build configuration, including compiler flags, feature flag values, and environment variables, at the time the binary is produced. That configuration record should be stored alongside the SBOM and referenced in the SBOM metadata so that an assessor can reconstruct the conditions under which the artifact was built.

Platform-Specific Transitive Dependencies

Transitive dependency resolution is another area where target variance creates SBOM gaps. A direct dependency that appears in all target builds may itself pull in different transitive dependencies depending on the platform. A cryptography library that uses native OS APIs on Windows may pull in different underlying packages than the same library compiled for Linux. Those transitive differences propagate vulnerability exposure in ways that are not visible from the top-level dependency list.

SBOM generation tools that operate after compilation, by inspecting the produced binary or the resolved dependency graph for a specific target, are better positioned to capture these transitive differences than tools that operate solely at the source manifest level. Federal programs should evaluate their SBOM tooling specifically for its ability to resolve and record transitive dependencies per target, not just per source component.

Build Matrix Governance and Artifact Digest Linkage

Build matrices are the standard mechanism for producing multiple target artifacts from a single pipeline run. A matrix build defines a set of target configurations and executes the build job once for each configuration, producing one artifact per target. From an SBOM governance perspective, each matrix job must be treated as an independent build event with its own SBOM output, its own artifact digest, and its own build configuration record.

The artifact digest is the anchor that makes SBOM traceability meaningful. Without a cryptographic digest linking the SBOM to the specific binary it describes, there is no reliable way to confirm that the SBOM was generated from the artifact that was actually delivered. For multi-target builds, this means each target artifact must be hashed immediately after production, before any post-processing or packaging steps, and that hash must be recorded in the corresponding SBOM and in the pipeline’s build provenance record.

Programs that use container image manifests for deployment have a natural anchor point in the image digest. Each platform-specific image in a multi-architecture manifest has its own digest, and that digest should correspond to a specific SBOM. The multi-architecture manifest index itself can reference the per-platform SBOMs, but the per-platform documents are the ones that support vulnerability correlation and assurance review for specific deployed instances.

Build provenance records, whether generated using an attestation framework or stored as pipeline artifacts, should capture the source commit, the build configuration, the toolchain versions, the target triple, and the artifact digest for each matrix job. That provenance record is what allows an assessor to trace a delivered binary back through the pipeline to the source commit and the SBOM that was generated for it, without relying on manual documentation that may not be maintained after initial delivery.

Validating Declared Versus Produced Artifacts

Generating a target-specific SBOM is necessary but not sufficient. The SBOM must be validated against the artifact it claims to describe. That validation has two dimensions: confirming that the artifact digest matches the binary that was delivered, and confirming that the SBOM’s dependency list matches what was actually compiled into the binary.

Artifact digest validation is straightforward in principle. The pipeline computes the digest of the produced binary, records it in the SBOM, and any downstream system that receives the binary can recompute the digest and compare it against the SBOM record. If the digests match, the binary has not been modified after the SBOM was generated. If they do not match, either the binary was tampered with or the SBOM was generated from a different artifact.

Dependency validation is more involved. It requires comparing the SBOM’s component list against an independent source of truth for what was compiled into the binary. For some ecosystems, that source of truth is the package manager’s lock file for the specific target resolution. For others, it may be a bill of materials generated by inspecting the binary directly, using symbol analysis or linked library enumeration. The comparison should flag any component that appears in the SBOM but not in the binary analysis, and any component found in the binary that does not appear in the SBOM.

Discrepancies between declared and produced artifacts are not always the result of tampering. They can result from dependency resolution differences between the SBOM generation tool and the build tool, from post-compilation linking steps that add libraries not captured during the initial SBOM generation, or from build environment drift where the toolchain or sysroot version changed between pipeline runs. Each discrepancy requires investigation, and the investigation findings should be documented as part of the build record for that artifact.

For programs subject to RMF assessment, the ability to produce a validated, target-specific SBOM with a matching artifact digest and a documented discrepancy resolution record is the kind of evidence that supports meaningful supply chain risk assessment. An SBOM that cannot be linked to a specific binary with a verified digest provides limited assurance regardless of how detailed its component list is.

Common Mistakes

The most common mistake in multi-target SBOM programs is generating a single SBOM from the source manifest and treating it as applicable to all target artifacts. This approach satisfies a checkbox requirement but does not provide the target-specific visibility needed to support accurate vulnerability correlation or assurance review. Programs that discover this gap during an assessment often find that correcting it requires significant pipeline rework, because the SBOM generation step was not designed with target isolation in mind.

A related mistake is running SBOM generation on the build host rather than in the target build environment. When a cross-compilation pipeline builds a Linux/ARM64 binary on a Linux/x86_64 host, an SBOM generator that queries the host’s package manager will produce a document reflecting the host’s dependency resolution, not the target’s. The resulting SBOM may list the correct package names but the wrong versions, or miss architecture-specific packages entirely.

Programs also frequently omit toolchain components from their SBOMs. The cross-compiler, linker, and sysroot are build inputs that affect the security posture of the produced binary. A vulnerability in a cross-compilation toolchain can introduce weaknesses into every binary produced by that toolchain. Omitting toolchain components from the SBOM means that toolchain vulnerabilities will not surface in standard SBOM-based vulnerability scans.

Another common gap is failing to link SBOMs to artifact digests at the time of generation. Programs that generate SBOMs as a post-delivery activity, or that store SBOMs separately from the artifacts they describe without a cryptographic linkage, cannot reliably demonstrate that a given SBOM corresponds to a given binary. That gap undermines the evidentiary value of the SBOM for both supply chain risk management and incident response.

Finally, programs that treat SBOM generation as a one-time delivery requirement rather than a continuous pipeline output will find that their SBOMs become stale quickly. Multi-target builds that update dependencies, change feature flags, or modify compiler configurations without regenerating target-specific SBOMs accumulate documentation debt that compounds over the lifecycle of the program. By the time an assessor or incident responder needs accurate SBOM data, the existing documents may reflect a build configuration that no longer matches any deployed artifact.

Recommended Federal Approach

Federal programs building for multiple targets should begin by auditing their existing SBOM generation practices against the target matrix they actually operate. That means listing every OS, processor architecture, build profile, and deployment target in the pipeline and confirming whether each one has a corresponding SBOM that was generated from the target-resolved dependency graph and linked to the artifact digest of the binary it describes. Most programs will find gaps at this stage, and the audit findings should drive the prioritization of remediation work.

The next step is to isolate dependency resolution per target in the build pipeline. That requires configuring package managers to resolve dependencies for the specific target architecture and operating system, not the host environment. For cross-compilation pipelines, this typically means using target-specific package manager configurations, sysroots, or containerized build environments that replicate the target platform’s dependency resolution behavior. The SBOM generation step should run after dependency resolution and compilation for each target, using the resolved dependency graph for that target as its input.

Toolchain capture should be added to the SBOM generation step for each target. The pipeline should record the compiler name and version, the target triple, the sysroot version, and any build-time code generators as structured metadata. That metadata should be embedded in the SBOM as build-time dependency relationships and stored in the build provenance record alongside the artifact digest.

Programs should implement automated validation as a pipeline gate before any artifact is promoted to a delivery or staging environment. That validation should compare the SBOM’s component list against the target-resolved dependency graph, verify the artifact digest, and flag discrepancies for review. Discrepancies should not automatically block delivery in all cases, but they should require documented resolution before the artifact is authorized for deployment in a production or operational environment.

For programs subject to RMF assessment, the target-specific SBOMs, build provenance records, and discrepancy resolution documentation should be maintained as part of the system’s continuous monitoring evidence. Assessors reviewing supply chain risk controls should be able to retrieve the SBOM for any deployed binary by querying the artifact registry using the binary’s digest or the target platform identifier. That capability requires a registry design that supports target-aware queries, not just version-based lookups.

Programs operating embedded or edge targets with constrained update cycles should plan for SBOM retention across the full deployment lifecycle of each artifact. An edge device running a binary for three years needs an SBOM that remains accessible and queryable for that entire period, even if the pipeline has since produced newer versions for other targets. Lifecycle sustainment planning for multi-target SBOM programs must account for the storage, indexing, and access requirements of long-lived artifact records across a heterogeneous target fleet.