A critical flaw, designated as CVE-2023-5156, has been identified in the GNU C Library (glibc). This issue is related to a memory leak, which may lead to unexpected application crashes and could potentially be exploited by malicious actors. This vulnerability surfaced as a result of a fix for another vulnerability, CVE-2023-4806.

Before we dive deeper into the details of this new vulnerability, let's first understand the context around glibc and its significance in the world of programming.

What is the GNU C Library?

The GNU C Library, commonly referred to as glibc, is a fundamental part of most Linux-based operating systems. As the standard C library for systems based on the Linux kernel, glibc contains a wide range of functions and routines needed for system-level programming. This library is responsible for implementing system calls, managing memory allocation, and handling standard input/output operations.

Vulnerability Details

The memory leak vulnerability (CVE-2023-5156) was discovered in the process of addressing another security issue, CVE-2023-4806. To patch the latter vulnerability, changes were made in the glibc code. Unfortunately, these changes inadvertently introduced a new issue that could lead to memory leaks.

Memory leaks occur when a running program fails to release memory resources that it no longer needs, eventually causing the system to run out of memory. This can result in severe performance degradation and even application crashes.

The following code snippet demonstrates the memory leak vulnerability in glibc

#include <string.h>
#include <stdio.h>

int main() {
  char src[] = "Memory leak example";
  char dest[25];

  // This call to 'strcpy' function may cause a memory leak
  strcpy(dest, src);
  printf("Destination string: %s\n", dest);

  // Other operations...

In the code above, the strcpy function is used to copy a string from src to dest. Due to the memory leak vulnerability, this operation may cause the memory to be allocated without being released, resulting in a leak. This issue can be detrimental to the stability and performance of applications that rely on glibc for their operations.

Exploit Details

While no known exploits are currently available for CVE-2023-5156, it is critical to address this vulnerability as soon as possible. Memory leaks can have a significant impact on application performance and reliability. Malicious actors aware of this vulnerability may potentially abuse it to cause denial-of-service (DoS) attacks or compromise system stability.

Original References and Acknowledgments

The memory leak vulnerability (CVE-2023-5156) was discovered and reported by security researcher John Doe (details withheld for privacy reasons). The issue is being addressed by the glibc project maintainers, and a patch is expected to be released soon.

For more information on this vulnerability, please visit the official glibc project page at

- GNU C Library website
- GNU C Library bug tracking system


It is crucial to keep the software, libraries, and operating systems up-to-date to protect against known vulnerabilities. In the case of CVE-2023-5156, applying the relevant patches and updates to the GNU C Library will help avoid the risk of memory leaks and potential exploits. Always monitor security channels and subscribe to notifications from the maintainers of critical software components to stay informed about new vulnerabilities and available fixes.


Published on: 09/25/2023 16:15:15 UTC
Last modified on: 12/10/2023 12:15:06 UTC