CVE-2018-25273: CrossFont 7.5 Buffer Overflow Vulnerability

CVE-2018-25273 Overview

CVE-2018-25273 is a buffer overflow vulnerability affecting CrossFont 7.5, a font conversion utility. The vulnerability allows local attackers to crash the application by submitting an oversized payload in the License Key field. By generating a malicious file containing 4000 bytes of data and pasting it into the License Key input field, attackers can trigger an application crash when the input is processed.

Critical Impact

Local attackers can cause a denial of service condition by exploiting improper input validation in the License Key field, leading to application crashes and potential disruption of font management workflows.

Affected Products

• CrossFont 7.5

Discovery Timeline

• 2026-04-26 - CVE CVE-2018-25273 published to NVD
• 2026-04-27 - Last updated in NVD database

Technical Details for CVE-2018-25273

Vulnerability Analysis

This vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input), commonly known as a classic buffer overflow. The application fails to properly validate the size of input data before copying it into a fixed-size memory buffer. When a user submits license key data exceeding the expected buffer size, the application writes beyond the allocated memory boundaries, corrupting adjacent memory and causing the application to crash.

The attack requires local access to the system where CrossFont 7.5 is installed. An attacker must be able to interact with the application's user interface to paste the malicious payload into the License Key field. While this vulnerability primarily results in a denial of service through application crashes, buffer overflows can sometimes be leveraged for more severe exploits depending on the memory layout and exploit development techniques.

Root Cause

The root cause of this vulnerability is insufficient input validation in the License Key processing functionality. The application allocates a fixed-size buffer for storing license key data but does not enforce proper bounds checking when copying user-supplied input into this buffer. When input exceeding approximately 4000 bytes is provided, the buffer is overflowed, leading to memory corruption and subsequent application crash.

Attack Vector

The attack vector is local, requiring the attacker to have access to a system with CrossFont 7.5 installed. The exploitation process involves creating a file containing approximately 4000 bytes of data, then pasting this oversized content into the License Key input field within the application. When the application attempts to process this input, the buffer overflow is triggered, causing the application to crash.

The vulnerability can be exploited without any special privileges or user interaction beyond the attacker's own actions. Technical details and proof-of-concept information are available through the Exploit-DB #45494 entry.

Detection Methods for CVE-2018-25273

Indicators of Compromise

• Unexpected CrossFont application crashes, particularly during license key entry operations
• Windows Event Log entries indicating application faults or access violations in CrossFont processes
• Presence of large text files (4000+ bytes) with random or patterned data that could be used as payloads

Detection Strategies

• Monitor for repeated application crashes of CrossFont executable using Windows Event Viewer or endpoint detection tools
• Implement application whitelisting to detect unauthorized clipboard operations involving large data payloads
• Deploy endpoint detection and response (EDR) solutions capable of identifying buffer overflow exploitation attempts

Monitoring Recommendations

• Enable crash dump collection for CrossFont processes to analyze potential exploitation attempts
• Configure SentinelOne Singularity platform to monitor for suspicious application behavior patterns
• Review system logs for patterns of repeated application failures that may indicate exploitation attempts

How to Mitigate CVE-2018-25273

Immediate Actions Required

• Restrict access to systems running CrossFont 7.5 to trusted users only
• Consider disabling or removing CrossFont 7.5 if not essential to operations until a patch is available
• Implement application control policies to prevent unauthorized use of the vulnerable application
• Monitor for any suspicious activity targeting CrossFont installations

Patch Information

No vendor patch information is currently available for this vulnerability. Users should consult the VulnCheck Security Advisory for updates on remediation options. Consider upgrading to a newer version of CrossFont if available, or switching to an alternative font conversion utility that is actively maintained.

Workarounds

• Limit physical and remote access to workstations where CrossFont 7.5 is installed
• Implement user training to avoid pasting untrusted content into application input fields
• Use application sandboxing or containerization to isolate CrossFont from critical system components
• Deploy SentinelOne endpoint protection to detect and prevent exploitation attempts