A new vulnerability, CVE-2025-26506, has been uncovered affecting several HP printing devices. This security flaw reveals that certain HP LaserJet Pro, LaserJet Enterprise, and LaserJet Managed Printers can be compromised by simply sending them a malicious print job. The issue lies in the way that the printers handle PostScript files — a common language used for printing tasks.

In this post, we’ll break down how CVE-2025-26506 works, what it means for your organization, and how attackers could exploit your network printers, using easy-to-understand language and even a code snippet to demonstrate. Let’s dive in.

What is CVE-2025-26506?

CVE-2025-26506 is a vulnerability that allows attackers to run code remotely (Remote Code Execution or RCE) and possibly gain higher privileges on the device (Privilege Escalation) by sending a specially crafted PostScript file as a print job. PostScript is basically a programming language for printers, so if there’s a bug in the way printers interpret this language, attackers can get the printer to do almost anything they want.

Which Devices are Affected?

HP has released a security advisory listing vulnerable models. Here are some known affected families (be sure to check the HP site for the complete list):

HP LaserJet Managed Printers

If your device is on the list, or if you haven't updated your printer's firmware lately, it's time to take notice!

How Does the Exploit Work?

The root of CVE-2025-26506 is in the PostScript interpreter embedded in the printers. When a user prints a malicious PostScript document, specially crafted commands inside the file can break out of the normal sandbox and run system commands. If the printer is accessible from the network, anyone with access to the print queue can attack.

Printer processes the file and, due to improper validation, executes unintended commands.

4. Attacker's code runs on the printer, potentially gaining control over it, and can access stored print jobs or use the printer as a foothold for further attacks.

Example Exploit (Code Snippet)

Here’s a basic demonstration PostScript file an attacker might use to execute a simple command (like opening a calculator, but on the printer). In reality, a real attack would be tuned to the printer's OS/firmware specifics.

%!PS
% Exploit snippet for CVE-2025-26506
% This is just for illustration; real exploits may differ.

userdict begin
  /system (id > /tmp/hp_rce_test.txt) (w) file
  dup  get 256 string readline pop
  closefile
end

Above, we try to execute a shell command (id) and write the output to a file on the printer’s filesystem. In a well-patched printer, this would fail. On a vulnerable one, it could succeed.

What are the Risks?

Remote Code Execution (RCE) lets an attacker run programs on your printer as if they were an authorized user. Privilege escalation means they could become the "admin" on the printer, changing settings, stealing documents, or even attacking other devices on your network.

Persistence: Attackers could install backdoors.

- Pivot to Internal Network: Compromised printers were used in real-world intrusions to attack other systems.

How to Defend Against This Vulnerability

1. Update Firmware: HP is releasing patches for affected models. Check here for firmware updates.
2. Limit Printer Access: Use network isolation (VLANs), require authentication, and limit which computers can send print jobs.
3. Disable Unused Print Languages: If you don’t need PostScript, disable it in the printer settings.

References

- HP Security Advisory - HP Printers - Potential Buffer Overflow, RCE, and EoP Vulnerabilities in Certain HP LaserJet Devices
- HP Firmware Update Search
- CVE-2025-26506 on NIST *(link will update as public details are released)*

Conclusion

Most people think of printers as simple office gear, but today’s multifunction printers are computers in their own right — and that means they need to be secured like any other device. CVE-2025-26506 is a stark reminder that even a harmless-looking print job can be weaponized if you’re not keeping your devices up to date. Make sure to patch your printers, watch your network, and treat every device as a potential entry point!

Timeline

Published on: 02/14/2025 17:15:22 UTC