The 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.

What CVEs are caused by CWE-441?

77 recorded CVEs are attributed to CWE-441, including CVE-2025-64125, CVE-2026-24471, CVE-2026-23751.

How do you prevent CWE-441?

Enforce the use of strong mutual authentication mechanism between the two parties.

How is CWE-441 detected?

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.)

What are the consequences of CWE-441?

Exploiting CWE-441 can lead to: Gain Privileges or Assume Identity, Hide Activities, Execute Unauthorized Code or Commands.

Is CWE-441 actively exploited?

77 recorded CVEs are caused by CWE-441; none are currently in CISA's KEV catalog of actively exploited flaws.

CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')

If an attacker cannot directly contact a target, but the product has access to the target, then the attacker can send a request to the product and have it be forwarded to the target. The request would appear to be coming from the product's system, not the attacker's system. As a result, the attacker can bypass access controls (such as firewalls) or hide the source of malicious requests, since the requests would not be coming directly from the attacker. Since proxy functionality and message-forwarding often serve a legitimate purpose, this issue only becomes a vulnerability when: The product runs with different privileges or on a different system, or otherwise has different levels of access than the upstream component; The attacker is prevented from making the request directly to the target; and The attacker can create a request that the proxy does not explicitly intend to be forwarded on the behalf of the requester. Such a request might point to an unexpected hostname, port number, hardware IP, or service. Or, the request might be sent to an allowed service, but the request could contain disallowed directives, commands, or resources.

CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Terminology & mappings

Alternate terms

Mapped taxonomies

Attack patterns

Frequently asked questions

What is CWE-441?

What CVEs are caused by CWE-441?

How do you prevent CWE-441?

How is CWE-441 detected?

What are the consequences of CWE-441?

Is CWE-441 actively exploited?

References

Stay ahead of CWE-441

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Related weaknesses

Parent

Child

Peer

Can precede

Related

Terminology & mappings

Alternate terms

Mapped taxonomies

Attack patterns

Frequently asked questions

What is CWE-441?

What CVEs are caused by CWE-441?

How do you prevent CWE-441?

How is CWE-441 detected?

What are the consequences of CWE-441?

Is CWE-441 actively exploited?

References

Stay ahead of CWE-441