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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 281

Data Poisoning

What is Data Poisoning?

Data PoisoningAn attack on a machine-learning system in which adversaries inject, alter, or relabel training data so the resulting model behaves incorrectly or contains hidden backdoors.


Data poisoning targets the training stage of the ML lifecycle. Attackers manipulate datasets — public web crawls, crowd-sourced labels, fine-tuning corpora, or feedback logs — to bias the model, degrade accuracy, or implant trigger-activated behaviour. Carlini et al. demonstrated in 2023 that even tiny fractions of poisoned web data can corrupt large pre-training corpora. Variants include availability attacks (degrade overall accuracy), targeted attacks (cause specific misclassifications), and backdoor attacks (activate on a chosen trigger). Defences focus on dataset provenance and signing, deduplication, anomaly detection on training data, robust learning algorithms, and continuous evaluation against benchmark and adversarial test sets.

Examples

  1. 01

    An attacker editing Wikipedia or expired domains so the polluted text is scraped into a future pre-training corpus.

  2. 02

    A malicious contributor submitting mislabeled samples to an open-source image-classification dataset.

Frequently asked questions

What is Data Poisoning?

An attack on a machine-learning system in which adversaries inject, alter, or relabel training data so the resulting model behaves incorrectly or contains hidden backdoors. It belongs to the AI & ML Security category of cybersecurity.

What does Data Poisoning mean?

An attack on a machine-learning system in which adversaries inject, alter, or relabel training data so the resulting model behaves incorrectly or contains hidden backdoors.

How does Data Poisoning work?

Data poisoning targets the training stage of the ML lifecycle. Attackers manipulate datasets — public web crawls, crowd-sourced labels, fine-tuning corpora, or feedback logs — to bias the model, degrade accuracy, or implant trigger-activated behaviour. Carlini et al. demonstrated in 2023 that even tiny fractions of poisoned web data can corrupt large pre-training corpora. Variants include availability attacks (degrade overall accuracy), targeted attacks (cause specific misclassifications), and backdoor attacks (activate on a chosen trigger). Defences focus on dataset provenance and signing, deduplication, anomaly detection on training data, robust learning algorithms, and continuous evaluation against benchmark and adversarial test sets.

How do you defend against Data Poisoning?

Defences for Data Poisoning typically combine technical controls and operational practices, as detailed in the full definition above.

What are other names for Data Poisoning?

Common alternative names include: Training data poisoning, Dataset poisoning.

Related terms

See also