A malicious-extension list is a registry-maintained record of extension IDs that have been flagged for suspected abuse, unsafe behavior, or policy violations. In software marketplaces, this list helps security teams, platform operators, and users identify add-ons that should be treated as risky even if they still look legitimate by name or description.
In cyber security, the list matters because extension ecosystems are a common supply-chain target. Attackers may publish lookalike packages, reuse familiar naming patterns, or abuse compromised publisher accounts to reach developers. A malicious-extension list can support blocking, warning, or takedown actions, but it is not a complete history: entries can be removed, restored, or reclassified over time. For that reason, defenders should preserve hashes, version data, publisher history, and timestamps so past abuse remains visible during investigations and threat hunting.