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CVE-2021-47815 is a denial of service vulnerability in Nsauditor 3.2.3, specifically affecting the registration code input field. The flaw resides in the software’s handling of user-supplied input, where the application fails to properly validate the length of the data before copying it into a fixed-size buffer. This is classified as CWE-120, a classic buffer copy without checking the size of input. When an attacker pastes a large buffer of 256 repeated characters into the ‘Key’ field, the application attempts to process this oversized input, leading to a buffer overflow that crashes the application. The vulnerability is local in nature, meaning the attacker must have access to the application’s registration interface, but no special privileges are required. The CVSS v4.0 score is Medium, reflecting the limited scope of the impact, which is primarily availability. The vulnerability was published on January 16, 2026, and last modified on May 1, 2026. The affected product is identified by CPE cpe:2.3:a:nsasoft:nsauditor, with versions up to but excluding 3.2.7. The crash occurs because the application does not enforce a maximum length on the input, allowing a controlled overflow that corrupts memory structures and triggers an exception. Exploitation is straightforward and requires no complex payload; a simple string of repeated characters is sufficient to cause the denial of service condition. The vulnerability has been assigned a Medium severity rating, with a CVSS v4.0 base score that reflects the local attack vector and the impact on availability only. The root cause is a lack of bounds checking in the registration code parsing logic, which has been a recurring issue in the Nsauditor product line. This CVE is one of several similar denial of service vulnerabilities reported for Nsauditor, highlighting a pattern of insufficient input validation. The vulnerability can be triggered by pasting a 256-character string into the registration key field, causing an immediate crash of the application. The exploit is trivial and does not require any specialized tools or knowledge, making it a low-skill attack. The impact is limited to a denial of service, as there is no evidence of code execution or data compromise. The vendor has not yet released an official patch, but the vulnerability is expected to be addressed in a future update. Users are advised to avoid pasting untrusted input into the registration fields until a fix is available.
DailyCVE Form:
Platform: Nsauditor
Version: 3.2.3
Vulnerability : DoS
Severity: Medium
date: 2026-01-16
Prediction: 2026-12-31
What Undercode Say:
Analytics:
Check for vulnerable version
nmap -sV --script nsauditor-version <target>
Trigger the DoS (educational)
python3 -c "print('A'256)" | xclip -selection clipboard
Paste into registration key field
Buffer overflow simulation
payload = "A" 256
print(f"Payload length: {len(payload)}")
This input crashes Nsauditor 3.2.3 when pasted into the Key field
Monitor crash strace -f -e trace=write ./nsauditor 2>&1 | grep -i "segfault"
Exploit: (Educational Purposes!)
1. Open Nsauditor 3.2.3.
2. Navigate to the registration dialog.
3. Generate a 256-byte string of repeated characters.
4. Paste the string into the ‘Key’ field.
5. Click OK or press Enter.
6. The application crashes immediately.
Protection: from this CVE
- Upgrade to Nsauditor 3.2.7 or later.
- Avoid pasting untrusted input into registration fields.
- Implement input validation for all user-supplied data.
- Use a memory-safe language for parsing registration codes.
- Apply the principle of least privilege when running the application.
Impact:
- Availability: Complete loss of availability for the affected application.
- Confidentiality: None.
- Integrity: None.
- Scope: Unchanged.
- User Interaction: Required (the user must paste the malicious input).
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Sources:
Reported By: github.com
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