A recently discovered vulnerability, labeled as CVE-2025-26506, has been identified as potentially impacting certain HP LaserJet Pro, HP LaserJet Enterprise, and HP LaserJet Managed Printers. This vulnerability, if exploited, could enable a threat actor to remotely execute code or elevate privileges on the target printer when processing a PostScript print job. This post aims to provide detailed information about the vulnerability, how it can be exploited, and the steps users can take to mitigate the risk.

HP LaserJet Managed series

For a complete list of affected printers, refer to an official HP advisory: [INSERT LINK TO HP ADVISORY]

Overview of the Vulnerability

CVE-2025-26506 is a Remote Code Execution (RCE) and Elevation of Privilege (EoP) vulnerability that stems from the way in which certain HP printers process PostScript print jobs. PostScript (PS) is a page description language and programming language, which is widely used for printing complex and high-quality documents.

The vulnerability lies in the way these affected HP printers interpret the PostScript data and lets an attacker craft a malicious PostScript print job to trigger the vulnerability. This can be used by an attacker to essentially conduct two types of attacks:

Remote Code Execution (RCE): The attacker could execute arbitrary code on the target printer.

2. Elevation of Privilege (EoP): The attacker could gain higher privileges on the target printer, allowing them to potentially make unauthorized changes to the printer's configuration or gain access to sensitive information stored on the printer.

Exploit Details

To exploit the vulnerability, an attacker must prepare a malicious PostScript print job containing certain crafted commands or data structures that would trigger the vulnerability when processed by the affected printer. The following is an example of a malicious PostScript code snippet that could potentially exploit this vulnerability:

%!PS
/buf 100 string def
/some_function{
    dup  lt { exit } if
    dup length buf length lt { exit } if
    buf  3 index putinterval
} def
Initial_Buffer_Overflow_Exploit_Payload
some_function

In this example, the attacker has defined a buffer named buf with a size of 100 bytes, and a malicious function named some_function. The Initial_Buffer_Overflow_Exploit_Payload placeholder is meant to represent the actual exploit payload constructed by the attacker. When this script is sent as part of a print job, the vulnerable HP printer could execute the embedded payload, resulting in either RCE or EoP.

Mitigation and Recommendations

HP has been made aware of the vulnerability and is working on providing firmware updates for the affected printers. It is highly recommended that users check for available firmware updates on a regular basis and apply them immediately when available.

In the meantime, users can take the following steps to mitigate the risk posed by CVE-2025-26506

1. Enable firmware signing: Ensure that the firmware signing feature is enabled on your HP printer. This will ensure that any firmware update you apply has been officially signed by HP and hasn't been tampered with by a threat actor.
2. Restrict access to printers: Where possible, configure your network and printer access controls to minimize the number of devices or users who can send print jobs to these printers. This will reduce the overall attack surface.
3. Educate users: Make users aware of potential threats associated with this specific vulnerability. Users should be informed not to print documents from untrusted sources or open suspicious attachments that might contain malicious PostScript content.

Conclusion

CVE-2025-26506 is a serious vulnerability that could potentially lead to remote code execution or elevation of privilege on certain HP LaserJet Pro, HP LaserJet Enterprise, and HP LaserJet Managed Printers. Users should take immediate steps to mitigate the risks associated with this vulnerability and apply available firmware updates as soon as they are released by HP.

Timeline

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