CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')
low-riskThe product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.
Common Consequences
Detection Methods
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.)
Real-World Examples (10)
| CVE | CVSS | EPSS | KEV |
|---|---|---|---|
| CVE-2020-5412 | 6.5 | 92.3% | — |
| CVE-2019-3924 | 7.5 | 10.8% | — |
| CVE-2019-3924 | 7.5 | 10.8% | — |
| CVE-2019-3996 | 6.5 | 3.5% | — |
| CVE-2022-39361 | 8.8 | 1.6% | — |
| CVE-2019-1841 | 6.5 | 1.2% | — |
| CVE-2021-20042 | 9.8 | 0.9% | — |
| CVE-2025-48710 | 4.1 | 0.7% | — |
| CVE-2021-25740 | 3.1 | 0.7% | — |
| CVE-2015-2947 | 9.1 | 0.5% | — |