Claude Code Bypasses Developer Deny Rules Silently
Anthropic’s Claude Code contains a critical parser bug that stops enforcing developer-configured deny rules when a compound command chain exceeds 50 subcommands. An attacker can hide a malicious payload after 50 benign subcommands (for example in a poisoned CLAUDE.md in an open-source repo). Because the legacy command parser drops deny-rule evaluation and falls back to a generic prompt — which can be auto-approved in CI/automation — secrets and credentials can be exfiltrated without warning. The issue was highlighted by security researchers and covered in early April 2026; a fix exists in Anthropic’s codebase per the initial researcher disclosure.
Scoring Rationale
This vulnerability is highly relevant to AI-assisted development workflows and tools (high relevance), affects a widely used product (moderate-to-high scope), and is actionable for practitioners (moderate). Multiple independent disclosures and coverage provide solid credibility; the bypass mechanism is novel in its simplicity but not unprecedented in supply-chain exploitation.
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Sources
- Read Original?Critical Claude Code Flaw Silently Bypasses User-Configured Security Rules