{"data":{"id":"9361797f-2af8-44ad-8abe-232731e25d8f","title":"LTBD: Learnable Trust-Boundary Delimiters for Prompt Injection Defense","summary":"Researchers introduce Learnable Trust-Boundary Delimiters (LTBD), a defense against prompt injection that uses a small number of learnable delimiters to separate trusted user instructions from untrusted external data, without changing LLM parameters. On AlpacaFarm, LTBD achieves 0.00% ASR, and on TaskTracker it achieves 0.11-0.19% ASR. The authors report that it outperforms inference-time defenses, is competitive with training-based approaches, and remains effective under adaptive attacks.","solution":"LTBD is the proposed defense: a lightweight method that adds learnable trust-boundary delimiters to the input to distinguish trusted user instructions from untrusted external data, keeping LLM parameters unchanged.","labels":["security","research"],"sourceUrl":"https://arxiv.org/abs/2610.11634v1","publishedAt":"2026-10-08T10:13:24.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":null,"severity":"info","attackType":["prompt_injection"],"issueType":"research","affectedPackages":null,"affectedPackageNames":null,"affectedPackageRefs":null,"affectedVendors":[],"affectedVendorsRaw":[],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":null,"headlinePromptVersion":null,"cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":null,"epssScore":null,"epssCheckedAt":null,"kevDateAdded":null,"advisoryAliases":null,"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":null,"disclosureDate":"2026-10-08T10:13:24.000Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["integrity","safety"],"aiComponentTargeted":"model","llmSpecific":true,"classifierConfidence":0.97,"researchCategory":"preprint","atlasIds":null}}