The product is built from multiple separate components, but it uses a component that is not sufficiently trusted to meet expectations for security, reliability, updateability, and maintainability.

Many modern hardware and software products are built by combining multiple smaller components together into one larger entity, often during the design or architecture phase. For example, a hardware component might be built by a separate supplier, or the product might use an open-source software library from a third party.
Regardless of the source, each component should be sufficiently trusted to ensure correct, secure operation of the product. If a component is not trustworthy, it can produce significant risks for the overall product, such as vulnerabilities that cannot be patched fast enough (if at all); hidden functionality such as malware; inability to update or replace the component if needed for security purposes; hardware components built from parts that do not meet specifications in ways that can lead to weaknesses; etc. Note that a component might not be trustworthy even if it is owned by the product vendor, such as a software component whose source code is lost and was built by developers who left the company, or a component that was developed by a separate company that was acquired and brought into the product's own company.
Note that there can be disagreement as to whether a component is sufficiently trustworthy, since trust is ultimately subjective. Different stakeholders (e.g., customers, vendors, governments) have various threat models and ways to assess trust, and design/architecture choices might make tradeoffs between security, reliability, safety, privacy, cost, and other characteristics.

Indirect

Requirements
Requirements might include criteria for which the only available solutions are provided by insufficiently trusted components.

Architecture and Design
An insufficiently trusted component might be selected because it is less expensive to do in-house, requires expertise that is not available in-house, or might allow the product to reach the market faster.

Other
Reduce Maintainability

Automated Static Analysis
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
High

Requirements
Architecture and Design
Implementation
For each component, ensure that its supply chain is well-controlled with sub-tier suppliers using best practices. For third-party software components such as libraries, ensure that they are developed and actively maintained by reputable vendors.

Architecture and Design
Implementation
Integration
Manufacturing
Maintain a Bill of Materials for all components and sub-components of the product. For software, maintain a Software Bill of Materials (SBOM). According to [REF-1247], "An SBOM is a formal, machine-readable inventory of software components and dependencies, information about those components, and their hierarchical relationships."

Operation
Patching and Maintenance
Continue to monitor changes in each of the product's components, especially when the changes indicate new vulnerabilities, end-of-life (EOL) plans, supplier practices that affect trustworthiness, etc.

A refrigerator has an Internet interface for the official purpose of alerting the manufacturer when that refrigerator detects a fault. Because the device is attached to the Internet, the refrigerator is a target for hackers who may wish to use the device other potentially more nefarious purposes.
The refrigerator has no means of patching and is hacked, becoming a spewer of email spam.
The device automatically patches itself and provides considerable more protection against being hacked.

CVE-2020-9054
Chain: network-attached storage (NAS) device has a critical OS command injection (CWE-78) vulnerability that is actively exploited to place IoT devices into a botnet, but some products are "end-of-support" and cannot be patched (CWE-1277). [REF-1097]
https://www.cve.org/CVERecord?id=CVE-2020-9054

Part 2-4
Req SP.03.02 RE(1)

Part 2-4
Req SP.03.02 RE(2)

Part 3-3
Req SR 1.13

Part 4-2
Req EDR 3.12

Part 4-2
Req HDR 3.12

Part 4-2
Req NDR 3.12

Part 4-2
Req EDR 3.13

Part 4-2
Req HDR 3.13

Part 4-2
Req NDR 3.13

Part 4-2
Req CR-7.8

Part 4-1
Req SM-6

Part 4-1
Req SM-9

Part 4-1
Req SM-10

Allowed-with-Review
This CWE entry is a Class and might have Base-level children that would be more appropriate
Examine children of this entry to see if there is a better fit

As of CWE 4.10, the name and description for this entry has undergone significant change and is still under public discussion, especially by members of the HW SIG.

CWE Content Team
MITRE
2022-04-20
4.7
2022-04-28

CWE Content Team
MITRE
2022-10-13
updated References

CWE Content Team
MITRE
2023-01-31
updated Applicable_Platforms, Description, Maintenance_Notes, Modes_of_Introduction, Name, Potential_Mitigations, Relationships

CWE Content Team
MITRE
2023-04-27
updated References, Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes, Taxonomy_Mappings

CWE Content Team
MITRE
2025-04-03
4.17
2025-04-03
updated Relationships

CWE Content Team
MITRE
2025-09-09
4.18
2025-09-09
updated References

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Demonstrative_Examples, Detection_Factors

"Mapping CWE to 62443" Sub-Working Group
CWE-CAPEC ICS/OT SIG
2023-06-29
4.12
2023-06-29
Suggested mappings to ISA/IEC 62443.

Reliance on Uncontrolled Component