CWE-252

Unchecked Return Value

Base

Draft

Description

The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions.

Two common programmer assumptions are "this function call can never fail" and "it doesn't matter if this function call fails". If an attacker can force the function to fail or otherwise return a value that is not expected, then the subsequent program logic could lead to a vulnerability, because the product is not in a state that the programmer assumes. For example, if the program calls a function to drop privileges but does not check the return code to ensure that privileges were successfully dropped, then the program will continue to operate with the higher privileges.

Parent Weaknesses (ChildOf)

CWE-754: Improper Check for Unusual or ...

Related Weaknesses

CWE-476 (CanPrecede)

Common Consequences

Scope

Availability

Integrity

Impact

Unexpected State, DoS: Crash, Exit, or Restart

Potential Mitigations

Implementation

Check the results of all functions that return a value and verify that the value is expected.

Implementation

For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished [REF-1484].

Implementation

Ensure that you account for all possible return values from the function.

Implementation

When designing a function, make sure you return a value or throw an exception in case of an error.

CVE-2020-17533

Chain: unchecked return value (CWE-252) of some functions for policy enforcement leads to authorization bypass (CWE-862)

CVE-2020-6078

Chain: The return value of a function returning a pointer is not checked for success (CWE-252) resulting in the later use of an uninitialized variable (CWE-456) and a null pointer dereference (CWE-476)

CVE-2019-15900

Chain: sscanf() call is used to check if a username and group exists, but the return value of sscanf() call is not checked (CWE-252), causing an uninitialized variable to be checked (CWE-457), returning success to allow authorization bypass for executing a privileged (CWE-863).

CVE-2007-3798

Unchecked return value leads to resultant integer overflow and code execution.

CVE-2006-4447

Program does not check return value when invoking functions to drop privileges, which could leave users with higher privileges than expected by forcing those functions to fail.

CVE-2006-2916

Program does not check return value when invoking functions to drop privileges, which could leave users with higher privileges than expected by forcing those functions to fail.

CVE-2008-5183

chain: unchecked return value can lead to NULL dereference

CVE-2010-0211

chain: unchecked return value (CWE-252) leads to free of invalid, uninitialized pointer (CWE-824).

CVE-2017-6964

Linux-based device mapper encryption program does not check the return value of setuid and setgid allowing attackers to execute code with unintended privileges.

CVE-2002-1372

Chain: Return values of file/socket operations are not checked (CWE-252), allowing resultant consumption of file descriptors (CWE-772).