Risk
Data and Model Poisoning
Training data, fine-tuning datasets, or embeddings are deliberately manipulated to introduce vulnerabilities, backdoors, or biases that compromise model security and behaviour.
- Domain
- Data
- Model
- Mechanism
- Integrity
- Boundary
- Between training, fine-tuning or embedding data and model weights
- Trigger
- Manipulated training or fine-tuning data is introduced
- Consequence
- Model integrity and behavior are compromised; backdoors or bias
- Required evidence
- Dataset provenance and hashes
- Training and fine-tuning audit records
- Behavioral backdoor testing
Exposure
Data poisoning occurs when an attacker interferes with the data used to train, fine-tune, or embed a model. The contamination may happen at any stage — during initial pre-training, vendor-supplied fine-tuning, third-party dataset ingestion, or user-provided feedback loops — and the effects persist silently until the model is queried.
The risk is compounded when organisations rely on pre-trained models from external sources without visibility into the training pipeline, or when fine-tuning datasets include public contributions, scraped content, or unverified third-party data.
Signals
- Unexplained degradation in model accuracy, safety behaviour, or refusal rates after a dataset update.
- Model responses diverge sharply from expected outputs for specific inputs or demographic groups.
- Training or fine-tuning data sources include user-contributed content without integrity verification.
- Vendor-supplied model updates lack a verifiable provenance chain or cryptographic signature.
Failure pattern
An attacker inserts malicious examples into a dataset that the target model will later consume. The model internalises the poison during training. At inference time, a trigger input — a specific phrase, image pattern, or data structure — activates the backdoor, causing the model to produce attacker-chosen outputs, bypass safety filters, or leak training data.
Related controls
- Verify provenance and integrity of all training and fine-tuning data sources.
- Maintain a controlled, versioned, and auditable data catalogue for each model version.
- Apply cryptographic signing to datasets and model artefacts.
- Monitor model behaviour after every data update for anomalous output patterns.
- Isolate user feedback loops from direct model retraining without human review.
Provenance
- SOURCE
-
- OWASP Top 10 for LLM Applications 2026 ↗ external_authority
- MAPPED
- Not recorded
- ANALYZED
- Not recorded
- UNRESOLVED
- Not recorded
Last reviewed: Sep 20, 2026