A new vulnerability, tracked as CVE-2023-43789, has been discovered in the libXpm library, an essential component used for displaying XPM (X Pixmap) images in the X Window System which is commonly found in Unix-like operating systems. This security flaw poses a threat to system memory as it allows a local user to perform an out-of-bounds read operation, potentially leaking sensitive data from the host machine.

Exploit Details

The vulnerability is caused by an inadequate boundary condition check in the libXpm library while processing an XPM file. When dealing with untrusted data, the improper handling of these conditions can result in out-of-bounds read errors. In this case, a specially crafted XPM file, when loaded, can lead to an inadvertent memory access allowing a malicious user to read sensitive information present in the system memory.

Here's a snippet of the vulnerable code section

// code snippet from libXpm - src/create.c

for (a = b = ; a < l; ) {
    register unsigned int uiTmp;

    s = , n = 1;
    if (INTEGER_OVERFLOW_ASSIGN(s, a << 2)) {
        return (XpmFileInvalid);
    if (c = unitchar(cmap[s])) {
        n = value;
        if (!*c && (ptr + a >= end))
    } else
        n--, a++;

The issue lies in the absence of a boundary check for the cmap array. When processing entries in the array, the index a can be incremented without checking if it exceeds the array boundaries, resulting in an out-of-bounds read access. A local user with the ability to provide a carefully crafted XPM file can exploit this vulnerability to read contents of memory on the system, potentially leaking sensitive information like cryptographic keys, passwords, etc.

Original References

- CVE-2023-43789
- libXpm

Impact and Mitigation

This vulnerability primarily affects systems using the libXpm library for handling and displaying XPM images. Successful exploitation of this vulnerability can lead to privacy concerns as a malicious user gains unauthorized access to sensitive data stored in the system memory.

It is advised to apply security updates and patches provided by the maintainers of the affected software as soon as they become available. Regularly updating software and adhering to secure coding practices are essential in preventing security vulnerabilities.


CVE-2023-43789 highlights the importance of proper boundary condition checks in software libraries, especially those handling untrusted data. Failure to adhere to secure coding practices can potentially expose sensitive system information to malicious users. Stay vigilant and update your software frequently to mitigate the risks associated with such vulnerabilities.


Published on: 10/12/2023 12:15:10 UTC
Last modified on: 11/07/2023 04:21:30 UTC