CVE-2021-47798: NoteBurner Buffer Overflow Vulnerability

CVE-2021-47798 Overview

CVE-2021-47798 is a buffer overflow vulnerability affecting NoteBurner version 2.35. The flaw exists in the license code input field where improper boundary checking allows attackers to trigger a denial of service condition. By generating a specially crafted 6000-byte payload and pasting it into the 'Name' and 'Code' fields of the application's registration dialog, an attacker can cause the application to crash.

Critical Impact

This buffer overflow vulnerability enables attackers to crash the NoteBurner application through malicious input in the license registration fields, resulting in denial of service.

Affected Products

• NoteBurner version 2.35

Discovery Timeline

• 2026-01-16 - CVE-2021-47798 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2021-47798

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 length of user-supplied input in the license registration fields before copying data into a fixed-size memory buffer. When input exceeding the expected buffer size is provided, the overflow corrupts adjacent memory regions, leading to application instability and crashes.

The local attack vector requires user interaction, as the victim must paste the malicious payload into the application's input fields. While this limits the attack scope compared to remote exploitation scenarios, the vulnerability demonstrates poor input validation practices that could potentially be leveraged for more severe attacks depending on the application's memory layout and security controls.

Root Cause

The root cause of CVE-2021-47798 is inadequate input validation in the NoteBurner license registration functionality. The application does not enforce proper length restrictions on the 'Name' and 'Code' input fields, allowing excessively long strings to be processed. The underlying buffer handling code copies user input without first verifying that the destination buffer has sufficient capacity to hold the data, resulting in a stack or heap buffer overflow condition.

Attack Vector

The attack requires local access to a system running NoteBurner 2.35. An attacker crafts a payload of approximately 6000 bytes and pastes this oversized string into either the 'Name' or 'Code' field within the application's license registration dialog. The overflow occurs when the application attempts to process this input, corrupting memory and causing the application to crash.

The vulnerability manifests when oversized input is supplied to the license registration fields. The application's input handling routine copies the user-supplied data into a fixed-size buffer without adequate bounds checking, leading to memory corruption. Technical details and proof-of-concept information can be found in the Exploit-DB #50154 entry.

Detection Methods for CVE-2021-47798

Indicators of Compromise

• NoteBurner application crashes or unexpected termination events
• Windows Event Log entries indicating application faults in NoteBurner processes
• Crash dump files containing stack traces related to buffer overflows
• Unusually large clipboard contents copied into the application

Detection Strategies

• Monitor for NoteBurner application crash events in system logs
• Implement endpoint detection rules to identify buffer overflow crash signatures
• Deploy application crash monitoring solutions to detect repeated denial of service attempts
• Use memory protection tools to identify heap or stack corruption events

Monitoring Recommendations

• Enable Windows Error Reporting to capture crash details for NoteBurner processes
• Configure endpoint protection to alert on suspicious application behavior
• Review system stability logs for patterns indicating exploitation attempts
• Implement SentinelOne Singularity for real-time behavioral analysis of application anomalies

How to Mitigate CVE-2021-47798

Immediate Actions Required

• Update NoteBurner to the latest available version if a patch has been released
• Restrict access to systems running the vulnerable NoteBurner version 2.35
• Implement application whitelisting to control which users can execute NoteBurner
• Consider using alternative software until a patched version is available

Patch Information

Users should check the NoteBurner Official Site for the latest software updates and security patches. The vendor should be contacted directly for information regarding fixed versions that address this buffer overflow vulnerability.

Workarounds

• Limit usage of the license registration feature until a patch is available
• Avoid copying and pasting content from untrusted sources into NoteBurner input fields
• Implement clipboard monitoring to detect abnormally large paste operations
• Use endpoint protection solutions like SentinelOne to detect and block exploitation attempts

For additional security guidance, consult the VulnCheck Advisory on NoteBurner for detailed mitigation recommendations.