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Subcommand Overflow Bypass - ATR-2026-00127 (6081ea63-ef75-57f0-8911-9f95f19f6589)

Detects SKILL.md files declaring an excessive number of subcommands or tools (>50). Claude Code has a security architecture where each subcommand is individually evaluated for safety. When a skill declares >50 subcommands, some implementations skip security checks on overflow commands due to performance budgets or fixed-size buffers. Attackers pad with 49 benign commands then add malicious ones at the end, expecting the security check to be skipped. Discovered via Claude Code leak analysis (2026-03).

Cluster A Galaxy A Cluster B Galaxy B Level
Subcommand Overflow Bypass - ATR-2026-00127 (6081ea63-ef75-57f0-8911-9f95f19f6589) Agent Threat Rules ML Supply Chain Compromise (d2cf31e0-a550-4fe0-8fdb-8941b3ac00d9) MITRE ATLAS Attack Pattern 1