Critical Heap Overflow in MS PostScript Driver Enables Remote Code Execution via Network

Microsoft disclosed a critical security flaw in its PostScript Printer Driver that permits remote code execution. The vulnerability, tracked as CVE-2026-70147, stems from a heap-based buffer overflow. An unauthorized attacker can exploit this defect over a network to run arbitrary code on a target system. This issue affects environments using the specified driver component.

Root cause

The underlying technical issue is a heap-based buffer overflow, identified by CWE-122. According to the Microsoft Security Update Guide, this weakness exists within the PostScript Printer Driver. The advisory describes the flaw as allowing an unauthorized attacker to execute code. The National Vulnerability Database confirms this classification. No further technical details on memory handling are provided in the source material.

Attack path

An attacker can trigger the vulnerability remotely over a network. The Microsoft advisory states that an unauthorized attacker can execute code over a network. This means a user without authorization can send malicious data to a system running the vulnerable driver. Once the overflow occurs, the attacker gains the ability to execute code. This provides a direct path to remote code execution.

Affected versions

The Microsoft Security Update Guide identifies the Microsoft PostScript Printer Driver as the affected component. The advisory does not specify particular version numbers or operating system releases in the provided text. It is necessary to check official vendor documentation for the exact list of impacted products. Any system utilizing this driver is potentially exposed.

Mitigation

• Apply the latest security updates from Microsoft as soon as they are available.
• Restrict network access to print services to reduce exposure.
• Monitor for unusual outbound connections from print server systems.
• Verify that the PostScript Printer Driver is enabled only where necessary.

Signals worth monitoring

Teams usually check for unexpected process creation on print server endpoints. Look for new binaries launching from unexpected directories after print jobs. Monitor for outbound network connections from print services to unknown destinations. Check for privilege escalation attempts by standard service accounts. Investigate any crashes or memory errors in the print spooler logs. These indicators often suggest exploitation attempts.

What to do and how to stay safe: Microsoft

• Verify that your systems are running the latest vendor-provided security updates.
• Segment your network to limit access to print services from untrusted zones.
• Enable detailed logging on print servers to capture unusual activity.
• Once the vendor provides an update, deploy it promptly to all affected hosts.

Step-by-step guide: Attack Surface Management: 6 Common Misreadings and Correct Views

General security guidance from the NetSec Observer newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is the CVSS score for CVE-2026-70147?

The National Vulnerability Database rates the severity at CVSS 9.8 CRITICAL.

Does the attacker need to log in to exploit this flaw?

The source states an unauthorized attacker can execute code over a network.

What type of vulnerability is this?

It is a heap-based buffer overflow in the Microsoft PostScript Printer Driver.