1. Vulnerability Description

• In case of capturing var in the Closure, the value may fluctuate according to the change of var, resulting in unintended results.

2. Vulnerability Countermeasure

• Check whether the use of var in the closure definition is done correctly, and it is recommended to use val to become a pure function.

3. Sample Code

• Vulnerable Code

class Test {
   var a = 1
   val b = List(1,2,3)
   val c = b.filter(_ < a)
}

• Safe Code
  • Use mkString

class Test {
   val a = 1
   val b = List(1,2,3)
   val c = b.filter(_ < a)
}