CWE-693: Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
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Overview
This weakness covers three distinct situations. A "missing" protection mechanism occurs when the application does not define any mechanism against a certain class of attack. An "insufficient" protection mechanism might provide some defenses - for example, against the most common attacks - but it does not protect against everything that is intended. Finally, an "ignored" mechanism occurs when a mechanism is available and in active use within the product, but the developer has not applied it in some code path.
Real-world CVEs
559 recorded CVEs are caused by CWE-693 (Protection Mechanism Failure), including 13 in CISA's KEV (Known Exploited Vulnerabilities) catalog. KEVs are shown first. 214 new CWE-693 CVEs have been recorded so far in 2026 (109 in 2025).