CWE-581: Object Model Violation: Just One of Equals and Hashcode Defined
CWE版本: 4.18
更新日期: 2025-09-09
弱点描述
The product does not maintain equal hashcodes for equal objects.
扩展描述
Java objects are expected to obey a number of invariants related to equality. One of these invariants is that equal objects must have equal hashcodes. In other words, if a.equals(b) == true then a.hashCode() == b.hashCode().
常见后果
影响范围: Integrity Other
技术影响: Other
说明: If this invariant is not upheld, it is likely to cause trouble if objects of this class are stored in a collection. If the objects of the class in question are used as a key in a Hashtable or if they are inserted into a Map or Set, it is critical that equal objects have equal hashcodes.
潜在缓解措施
阶段: Implementation
描述: Both Equals() and Hashcode() should be defined.
检测方法
方法: 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.)
有效性: High
引入模式
| 阶段 | 说明 |
|---|---|
| Implementation | - |
适用平台
编程语言
分类映射
| 分类名称 | 条目ID | 条目名称 | 映射适配度 |
|---|---|---|---|
| The CERT Oracle Secure Coding Standard for Java (2011) | MET09-J | Classes that define an equals() method must also define a hashCode() method | - |