CVE-2025-27831 - Buffer Overflow Vulnerability in Artifex Ghostscript DOCXWRITE and TXTWRITE devices

A new vulnerability with the Common Vulnerabilities and Exposures (CVE) identifier "CVE-2025-27831" has been discovered in the popular open-source software package Artifex Ghostscript. This vulnerability affects versions of Ghostscript before 10.05. and can lead to potential buffer overflow attacks. Artifex Ghostscript is a high-performance PostScript and PDF interpreter that is widely employed in a variety of applications that involve the rendering and manipulation of documents.

This article offers an in-depth analysis of the CVE-2025-27831 vulnerability, its exploitation details, and potential mitigations. We will also provide links to original references and code snippets to help users understand, identify, and address this security concern.

Exploit Details

The CVE-2025-27831 vulnerability exists in the DOCXWRITE and TXTWRITE devices in Artifex Ghostscript. These devices are responsible for writing Microsoft Word (DOCX) and plain text (TXT) files, respectively. The vulnerability arises from a buffer overflow caused by long characters being written to the devices/vector/doc_common.c file.

A buffer overflow occurs when a program writes more data to a buffer than it was designed to hold. In the case of Ghostscript's DOCXWRITE and TXTWRITE devices, this vulnerability can be triggered when characters that are longer than the buffer space allocated for the devices are written to doc_common.c.

Exploiting this vulnerability can potentially lead to code execution or denial of service attacks, which can compromise the security and reliability of systems employing Ghostscript for document processing tasks.

Code Snippet

The problematic code responsible for the vulnerability can be found in the doc_common.c file, within the write_text_fragment function:

void write_text_fragment(stream *, const char *); 

... 

static void write_draw_text(prolog_writer Device, const gs_text_enum_t *penum)
{
...
while ((code = (int)gx_path_enum_next(&path_enum, (gs_fixed_point *)pep)) > ) {
    if (code == gs_pe_newpoint) {
        ...
    } else {
        ...
        write_text_fragment(Device->strm, chars_buffer); // Buffer overflow occurs here
    }
}
...
}
...
}

As shown in the code snippet, the write_text_fragment function is called, passing the chars_buffer parameter. The issue stems from the fact that there is no validation present to ensure that the length of chars_buffer does not surpass the allocated buffer size.

Original References

The details of the CVE-2025-27831 vulnerability are publicly available on several platforms. These include the following official sources:

- CVE-2025-27831 - National Vulnerability Database (NVD)
- Artifex Ghostscript - Official Website

Mitigation

To address the CVE-2025-27831 vulnerability, users are advised to update their implementation of Artifex Ghostscript to version 10.05. or later. This update includes fixes for the issue and ensures that the buffer overflow no longer occurs when processing documents with the DOCXWRITE and TXTWRITE devices. Users can download the latest version of Ghostscript from the Artifex Ghostscript download page.

Conclusion

The CVE-2025-27831 vulnerability demonstrates the importance of continually auditing and updating software to minimize security risks. By understanding the issue and applying the appropriate patches, users can help safeguard their systems from potential attacks related to this vulnerability. As always, it is essential to remain vigilant and proactive in addressing software security concerns.

Timeline

Published on: 03/25/2025 21:15:42 UTC
Last modified on: 04/01/2025 16:44:41 UTC