[metadata]
id = "MEM31-C"
type = "rule"
category = "MEM"
number = 31
title = "Free dynamically allocated memory when no longer needed"
description = """
Before the lifetime of the last pointer that stores the return value of a call
to a standard memory allocation function has ended, it must be matched by a call
tofree()with that pointer value. In this noncompliant example, the object
allocated by the call tomalloc()is not freed before the end of the lifetime of
the last pointertext_bufferreferring to the object: #include <stdlib.h> enum {
BUFFER_SIZE = 32 }; int f(void) { char *text_buffer = (char
*)malloc(BUFFER_SIZE); if (text_buffer == NULL) { return -1; } return 0; }
"""
severity = "Medium"
likelihood = "Probable"
priority = "P4"
level = "L3"
cert_version = "2016 Edition (Wiki)"
last_modified = "Aug 06, 2025"
[rules.cert_c.MEM31-C]
enabled = true
[references]
wiki = "https://wiki.sei.cmu.edu/confluence/display/c/MEM31-C.+Free+dynamically+allocated+memory+when+no+longer+needed"
cwe = ["CWE-401", "CWE-404", "CWE-459", "CWE-771", "CWE-772"]