CWE-462 Duplicate Key in Associative List (Alist)

Duplicate keys in associative lists can lead to non-unique keys being mistaken for an error.

• Other: Quality Degradation, Varies by Context — If an alist contains duplicate key entries, this introduces an ambiguity in which it cannot be predicted which key value will be selected.

• [Implementation] Use a hash table instead of an alist. • [Implementation] Use an alist which checks the uniqueness of hash keys with each entry before inserting the entry. • [Implementation] Duplicate key entries in an association list are not recommended and should not be allowed.

• Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)