{"data":{"id":"de308540-8291-4ffc-81dd-e680626a54b7","title":"LEANGUARD: Lean-Verified Guardrails for Tool-Using Agents","summary":"LeanGuard is a runtime that checks each tool call an LLM agent proposes against a policy written in Lean4 before the call executes, using fail-closed evaluation over state predicates and scoped past-time temporal operators. On Tau-Bench with five Qwen models (0.8B-27B), unguarded agents executed at least 33 forbidden calls while LeanGuard executed none, and on DTap it cut direct prompt-injection success from 57.9% to 5.9%.","solution":"N/A -- no mitigation discussed in source.","labels":["security","research"],"sourceUrl":"https://arxiv.org/abs/2611.02332v1","publishedAt":"2026-11-02T00:26:48.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":null,"severity":"info","attackType":["prompt_injection"],"issueType":"research","affectedPackages":null,"affectedPackageNames":null,"affectedPackageRefs":null,"affectedVendors":[],"affectedVendorsRaw":["Qwen"],"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":"2026-11-02T00:26:48.000Z","fixReleasedAt":null,"daysToFix":null,"fixCheckedAt":null,"capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["integrity","safety"],"aiComponentTargeted":"agent","llmSpecific":true,"classifierConfidence":0.95,"researchCategory":"preprint","atlasIds":["AML.T0051"]}}