Page History

...

class S {
  int c;
 
public:
  S() : c(0) {}
  int f(int i) const { return i + c; }
};
 
void f() {
  S s;
  int i = s.f(10);
}

Noncompliant Code Example (Uninitialized delete)

In this noncompliant code example, two allocations are attempted within the same try block, and if either fails, the catch handler attempts to free resources that have been allocated. However, because the pointer variables have not been initialized to a known value, a failure to allocate memory for i1 will result in reading the uninitialized i2, resulting in undefined behavior.

#include <new>
 
void f() {
  int *i1, *i2;
  try {
    i1 = new int;
    i2 = new int;
  } catch (std::bad_alloc &) {
    delete i1;
    delete i2;
  }
}

Compliant Solution (Uninitialized delete)

This compliant solution initializes both pointer values to nullptr.

#include <new>
 
void f() {
  int *i1 = nullptr, *i2 = nullptr;
  try {
    i1 = new int;
    i2 = new int;
  } catch (std::bad_alloc &) {
    delete i1;
    delete i2;
  }
}

Risk Assessment

Reading uninitialized variables is undefined behavior and can result in unexpected program behavior. In some cases, these security flaws may allow the execution of arbitrary code.

...