CWE-692

Compound Abstraction Level
Pillar — Highest-level weakness category
Class — Abstract, language-independent
Base — Specific enough to detect
Variant — Tied to specific technology
Compound — Requires multiple weaknesses Draft MITRE CWE Status
Stable — Fully reviewed and complete
Draft — Under development, may change
Incomplete — Partially defined by MITRE
Deprecated — No longer recommended
Obsolete — Replaced by another CWE
Incomplete Denylist to Cross-Site Scripting

Description

The product uses a denylist-based protection mechanism to defend against XSS attacks, but the denylist is incomplete, allowing XSS variants to succeed.

While XSS might seem simple to prevent, web browsers vary so widely in how they parse web pages, that a denylist cannot keep track of all the variations. The "XSS Cheat Sheet" [REF-714] contains a large number of attacks that are intended to bypass incomplete denylists.

Consequences

Confidentiality, Integrity, Availability — Execute Unauthorized Code or Commands