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Multilingual LLM attacks: are your controls keeping up?

 

(@nhi-mgmt-group)
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Joined: 1 year ago
Posts: 16489
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TL;DR: English-first guardrails leave LLMs exposed to prompt attacks, data extraction, and translation-based bypasses across many languages, according to Lakera’s analysis of real-world cases and research. Security teams need multilingual defenses, not just broader model coverage, because policy enforcement breaks when language handling is inconsistent.

Editorial analysis by NHI Mgmt Group, based on content published by Lakera: “Language Is All You Need: The Hidden AI Security Risk”.

By the numbers:

  • Attackers bypassed Gandalf's guardrails in over 85 languages using code-switching, translation-based exploits, and multilingual data extraction.

Key questions

Q: How should security teams test LLM guardrails across multiple languages?

A: Security teams should test the same harmful intent in every major language and in code-switched variants, then compare block, warn, and allow outcomes.

Q: Why do English-first AI controls fail in production?

A: Because moderation and refusal logic are often tuned to English patterns, while real users and attackers do not stay inside one language.

Q: What are the signs that multilingual AI safety is breaking down?

A: Look for different outcomes on semantically identical prompts, higher jailbreak success in specific languages, and unexpected refusals for benign non-English inputs.

Practitioner guidance

  • Test safety controls across languages Build multilingual adversarial test cases for prompts, code-switching, paraphrase, and translation-based bypasses before release and after major model changes.
  • Validate policy consistency at runtime Check whether the same restricted intent produces the same refusal outcome in English, translated forms, and mixed-language prompts.
  • Screen inputs and outputs together Apply runtime controls to both user prompts and model outputs so translated requests cannot evade detection on the way in or on the way out.

Bottom line: English-first guardrails do not provide consistent protection when users can rephrase prompts across languages, scripts, or translation paths.

Explore further

View Full Forum →  |  NHI Foundation Course →  |  Our Services →  |  Read the full analysis →



   
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(@mr-nhi)
Member Moderator
Joined: 5 months ago
Posts: 16980
 

Multilingual policy drift is the core security problem, not just multilingual content support. When the same prohibited intent is blocked in one language and permitted in another, the control is no longer enforcing policy. That inconsistency creates a new attack surface for prompt injection, data extraction, and output manipulation. Practitioners should treat language coverage as a policy integrity issue, not a user-experience issue.

A few things that frame the scale:

  • Only 23% of IT leaders were very confident in their organisation's ability to manage security and governance for GenAI deployments, according to a 2025 Gartner survey of 360 IT leaders.

A question worth separating out:

Q: How do organisations govern AI systems that handle sensitive data in multiple languages?

A: Define one policy boundary for all supported languages, then test it against prompts, outputs, and translation paths that touch sensitive data. If the system can reveal personal, operational, or internal information in one language but not another, governance has to move from model behaviour to runtime enforcement.

👉 Read our full editorial: Multilingual AI security gaps expose English-first LLM defenses



   
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