Taint

Taint is a term used to describe contamination or corruption that spoils something's cleanliness, safety, or integrity. As a verb, to taint means to contaminate or to corrupt; as a noun, a taint is a stain, blemish, or source of contamination. The word derives from Old French taindre, meaning to dye or color, with the figurative sense of staining extended to moral or reputational blemish.

In everyday language, taint commonly refers to physical contamination: tainted food or water; taint by pathogens, chemicals, or pollutants; environmental taint such as tainted soil or air. The term is used in public health, food safety, and environmental monitoring to indicate that an agent has compromised safety or quality. Taint can be transient or persistent; remediation aims to remove the taint and restore safety and integrity.

In computing, taint analysis is a form of dynamic or static program analysis that tracks data originating from untrusted inputs (such as user input or network data) as it flows through a program. The goal is to detect security vulnerabilities where untrusted data could influence critical operations, such as database queries or file system access. Taint tracking marks data as tainted at the source and propagates the status until it reaches a sink, where analysis can raise warnings or block execution.

In general usage, taint also refers to moral or reputational blemish. A person or institution can be tainted by scandal or wrongdoing, a phrase often used metaphorically to indicate loss of trust or credibility.