Ghostscript flaw lets hackers hijack servers via PDF uploads
Critical vulnerability in Ghostscript could lead to remote code execution via PDF uploads, affecting WordPress and other systems running Ghostscript 9.21-10.07.1.
Intelligence analysis by Qwen 2.5 (3B)
A critical vulnerability in Ghostscript, a PostScript and PDF interpreter, could allow hackers to execute arbitrary code remotely through PDF uploads, impacting WordPress and other systems.
A bug in a program called Ghostscript could let bad guys make a special PDF file that tricks the program into doing something it shouldn't, like letting them run their own code on a computer. This could happen on websites that use Ghostscript to show PDFs.
Analysis
{"
Vulnerability Details and Discovery":"The vulnerability, CVE-2026-39919, is a heap buffer overflow in the Ghostscript interpreter and rendering engine, discovered by researchers at Defiant's Wordfence platform using their Argus AI-powered system.","
Exploitation and Proof-of-Concept (PoC) Exploits":"Wordfence developed two PoC exploits that trigger the vulnerability. The exploits require specific modifications to the PDF file, such as changing fonts, language settings, and core system libraries.","
Affected Systems":"The vulnerability affects any online system running Ghostscript 9.21 through 10.07.1. Wordfence tested ten Linux environments, including Debian, Ubuntu, Fedora, Alpine, and AlmaLinux, and found all contained the vulnerable code.","
Exploitation Prerequisites":"For successful exploitation, an attacker must upload a PDF, process it to generate a preview or thumbnail, and ensure Ghostscript is involved in the processing chain. Authentication requirements depend on the application.","
Fix and Mitigation":"Artifex, the maintainer of Ghostscript, released a fix in version 10.08.0. Users should check the revision details for patch status. WordPress administrators need to ensure Ghostscript has been upgraded to version 10.08.0 or later.","
In-the-Wild Status":"Wordfence has not seen any in-the-wild exploitation of CVE-2026-39919 yet. However, the vulnerability could pose a significant risk to systems running Ghostscript, especially in environments where PDFs are processed and rendered."}
Key points
- CVE-2026-39919 is a critical heap buffer overflow vulnerability in Ghostscript.
- The vulnerability affects systems running Ghostscript 9.21 through 10.07.1.
- Wordfence developed two PoC exploits that trigger the vulnerability.
- The vulnerability could lead to remote code execution, posing a significant risk to systems.
- Artifex released a fix in version 10.08.0, and users should check for the latest version.
With the fix released, the risk of this bug being used to cause problems has decreased. Users should check for the latest version of Ghostscript and ensure it is installed.
If the bug is used, it could lead to remote code execution, which means the attacker could control parts of the system. Users should stay updated and take precautions to protect their systems.
