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In early 2025, the Norwegian Supreme Court identified a legal filing containing fabricated citations and quotes, which had been generated by an AI tool and submitted by an attorney without verification. The court detected the hallucinations during routine review and subsequently updated its lawyer guidance to emphasize professional responsibility and the necessity of verifying AI-generated content. No sanctions were issued in this instance, but the court signaled that future occurrences could lead to disciplinary action.
In early 2025, Norway’s Supreme Court (Høyesterett) received a legal filing containing hallucinated legal citations and quotes, allegedly inserted by an attorney using an AI tool without verification. The fabricated sources were detected during standard review. While no sanctions were issued, the Court updated its guidance to lawyers, warning that AI use does not exempt them from professional responsibility.
Domain classification, causal taxonomy, severity scores, and national security assessments were LLM-classified and may contain errors.
AI systems that inadvertently generate or spread incorrect or deceptive information, which can lead to inaccurate beliefs in users and undermine their autonomy. Humans that make decisions based on false beliefs can experience physical, emotional or material harms
Also classified as
The attorney relied on the AI-generated text and submitted the legal brief to the Supreme Court without verifying the sources, demonstrating unsafe use and overreliance.
The AI system generated fabricated legal citations and non-existent legal sources, which constitutes false and misleading information that was subsequently submitted to a court of law.
AI system
Due to a decision or action made by an AI system
Unintentional
Due to an unexpected outcome from pursuing a goal
Post-deployment
Occurring after the AI model has been trained and deployed
The risk was caused by the AI system generating fabricated legal citations (hallucinations) during its post-deployment use, which was an unexpected and unintended outcome of its operation.
Added categories peak at 2: Minor (Epistemic Harm, Direct)
An attorney submitted a civil legal filing to the Norwegian Supreme Court containing AI-generated fake citations. The court detected the hallucinations and updated its lawyer guidelines. The incident represents a minor, localized impact on government operations with negligible national security implications.
The AI system acted as an assistant to the lawyer, generating text and legal citations to help draft the legal brief, which required human oversight and verification before submission.
Risk Level 3. Limited Risk: The incident involves the use of a general-purpose AI system (likely a chatbot or text generator) to produce AI-generated content, which falls under the Limited Risk category requiring transparency and verification.
The AI system was used by an attorney to draft a legal brief and generate legal citations, which is a core function of a writing assistant.
The report from a reputable Norwegian legal news outlet clearly details the incident, including statements from the Chief Justice of the Supreme Court. The facts regarding the AI's hallucination of legal sources and the lawyer's failure to verify them are explicit and uncontested.
None. The event is straightforwardly an instance of AI hallucination in a legal context.
Technology
AI Hallucination
The AI tool generated fictitious legal sources and preparatory works.
Lack of Source Validation
The generative AI model lacked built-in validation for Norwegian legal facts.
Data Inputs
Plausible but Fake Data
AI training patterns allowed generation of highly realistic but fake citations.
Human Factors
Failure to Verify Sources
The lawyer did not check the AI-generated sources before submitting the brief.
Overreliance on AI Tool
The lawyer trusted the AI output without performing standard due diligence.
Insufficient AI Competence
The lawyer lacked understanding of AI risks like hallucination.
Process and Methods
Lack of Quality Control
No internal peer review or citation verification process was used.
Management
Lack of Firm Support
The lawyer did not have a large firm's internal support and guidance.
Regulatory Environment
Outdated Court Guidelines
The Supreme Court guidelines lacked explicit instructions on AI use.
Unclear Professional Standards
Lack of explicit ethical guidelines from the Bar Association on AI.
AI system involved
An AI system was involved, but the reports do not identify it.
Identified by automated extraction; can differ from the alleged developers above.
