CWE-201

Base Abstraction Level
Pillar — Highest-level weakness category
Class — Abstract, language-independent
Base — Specific enough to detect
Variant — Tied to specific technology
Compound — Requires multiple weaknesses Draft MITRE CWE Status
Stable — Fully reviewed and complete
Draft — Under development, may change
Incomplete — Partially defined by MITRE
Deprecated — No longer recommended
Obsolete — Replaced by another CWE
Insertion of Sensitive Information Into Sent Data

Description

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.

Top Monitored CVEs

CVE-2026-24477
HIGH
7.5 1.6%
2026-01-26

Consequences

Confidentiality — Read Files or Directories, Read Memory, Read Application Data

Sensitive data may be exposed to attackers.

Mitigations

Phase: Requirements

Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.

Phase: Implementation

Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere. Any information that is not necessary to the functionality should be removed in order to lower both the overhead and the possibility of security sensitive data being sent.

Phase: System Configuration

Setup default error messages so that unexpected errors do not disclose sensitive information.

Phase: Architecture and Design

Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Detection

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.)