CVE-2021-47821: RarmaRadio DoS Vulnerability

CVE-2021-47821 Overview

RarmaRadio 2.72.8 contains a denial of service vulnerability that allows attackers to crash the application by overflowing network configuration fields with large character buffers. This improper validation of specified quantity in input flaw (CWE-1284) enables attackers to generate a 100,000 character buffer and paste it into multiple network settings fields to trigger application instability and potential crash.

Critical Impact

Local attackers can cause application instability and crashes by exploiting improper input validation in network configuration fields, resulting in denial of service for RarmaRadio users.

Affected Products

• RarmaRadio version 2.72.8
• Network configuration fields within the application settings

Discovery Timeline

• 2026-01-16 - CVE CVE-2021-47821 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2021-47821

Vulnerability Analysis

This vulnerability stems from improper validation of input length in RarmaRadio's network configuration interface. The application fails to properly restrict the size of user-supplied data when processing network settings fields. When an attacker provides an excessively large input buffer (approximately 100,000 characters) to these configuration fields, the application cannot handle the data appropriately, leading to memory corruption or resource exhaustion that results in application instability or a complete crash.

The vulnerability requires local access and user interaction to exploit, as the attacker must either have direct access to the application or convince a user to paste malicious content into the configuration fields. While the impact is limited to availability (denial of service), this can disrupt users who rely on the application for internet radio functionality.

Root Cause

The root cause is classified as CWE-1284 (Improper Validation of Specified Quantity in Input). RarmaRadio's network configuration module does not implement proper bounds checking or input length validation before processing user-supplied data. The application assumes input will be within reasonable limits and fails to sanitize or truncate excessively large strings before attempting to process them.

Attack Vector

The attack vector is local, requiring the attacker to have access to the target system where RarmaRadio is installed. Exploitation involves generating a large character buffer (100,000 characters) and pasting this content into one or more network settings fields within the application. This can be accomplished through direct user access or through social engineering techniques that convince a legitimate user to paste malicious content from the clipboard.

The attack does not require elevated privileges, but does require user interaction to trigger the vulnerable code path through the application's configuration interface.

Detection Methods for CVE-2021-47821

Indicators of Compromise

• Unexpected RarmaRadio application crashes or hangs during configuration changes
• Large clipboard contents being pasted into application fields
• Memory usage spikes associated with the RarmaRadio process
• Application error logs indicating buffer or memory-related issues

Detection Strategies

• Monitor for RarmaRadio process crashes or abnormal terminations
• Implement endpoint detection rules for applications experiencing repeated crash events
• Deploy application monitoring to detect excessive memory consumption by RarmaRadio
• Review Windows Event Logs for application fault entries related to RarmaRadio

Monitoring Recommendations

• Enable crash dump collection for the RarmaRadio application to capture forensic data
• Implement endpoint monitoring for unusual application behavior patterns
• Consider application whitelisting policies to control which users can modify network settings
• Deploy SentinelOne Singularity to detect and respond to denial of service attack patterns

How to Mitigate CVE-2021-47821

Immediate Actions Required

• Verify the installed version of RarmaRadio and check for available updates from the vendor
• Restrict access to network configuration settings to trusted users only
• Consider temporarily disabling or removing RarmaRadio if it is not critical to operations
• Educate users about not pasting untrusted content into application configuration fields

Patch Information

No official patch information is available at this time. Users should monitor the Raimersoft Home Page for security updates and new versions that may address this vulnerability. Additional technical details can be found in the Vulncheck Advisory on RARmaradio and Exploit-DB #49906.

Workarounds

• Limit clipboard access to the RarmaRadio application where possible
• Implement user training to avoid pasting large or untrusted content into application fields
• Consider using alternative internet radio applications until a patch is available
• Deploy application control policies to restrict network configuration changes to authorized personnel only