CVE-2016-20043: NRSS RSS Reader Buffer Overflow Flaw

CVE-2016-20043 Overview

NRSS RSS Reader version 0.3.9-1 contains a stack buffer overflow vulnerability (CWE-787: Out-of-bounds Write) that allows local attackers to execute arbitrary code. The vulnerability exists in the handling of the -F parameter, where supplying an oversized argument triggers a stack buffer overflow condition. Attackers can craft malicious input with 256 bytes of padding followed by a controlled EIP value to overwrite the return address and achieve code execution on affected systems.

Critical Impact

Local attackers can achieve arbitrary code execution by exploiting this stack buffer overflow, potentially leading to complete system compromise with the privileges of the user running the NRSS application.

Affected Products

• NRSS RSS Reader version 0.3.9-1

Discovery Timeline

• 2026-03-28 - CVE CVE-2016-20043 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2016-20043

Vulnerability Analysis

This vulnerability is classified as a stack buffer overflow (CWE-787: Out-of-bounds Write), a memory corruption vulnerability that occurs when the application writes data beyond the allocated buffer boundaries on the stack. The NRSS RSS Reader fails to properly validate the length of user-supplied input when processing the -F command-line parameter, allowing attackers to overflow a fixed-size buffer on the stack.

The attack requires local access to the system where NRSS is installed. No user interaction is required beyond running the application with the malicious argument. Upon successful exploitation, the attacker gains code execution capabilities with the same privileges as the application process.

Root Cause

The root cause of this vulnerability is insufficient bounds checking when copying user-supplied data from the -F parameter into a fixed-size stack buffer. The application does not validate that the input length is within the expected boundaries before performing the copy operation, resulting in a classic stack-based buffer overflow condition.

Attack Vector

This is a local attack vector vulnerability requiring the attacker to have access to execute the NRSS application on the target system. The exploitation methodology involves crafting an argument to the -F parameter that exceeds the expected buffer size.

The exploit requires 256 bytes of padding to reach the saved return address on the stack, followed by a 4-byte value that overwrites the EIP (Instruction Pointer) register. By controlling EIP, the attacker can redirect execution flow to arbitrary code, such as shellcode placed within the overflow payload or existing code gadgets for return-oriented programming (ROP) attacks.

For detailed technical information and proof-of-concept details, refer to the Exploit-DB #39810 entry and the VulnCheck Advisory on NRSS Buffer Overflow.

Detection Methods for CVE-2016-20043

Indicators of Compromise

• Execution of NRSS with abnormally long command-line arguments, particularly to the -F parameter
• Application crashes or segmentation faults when running NRSS with unusual input patterns
• Unexpected child processes spawned by the NRSS application
• Signs of code execution following NRSS termination, such as new network connections or file modifications

Detection Strategies

• Monitor command-line arguments passed to NRSS processes for excessive length or suspicious patterns
• Implement application whitelisting to control which arguments can be passed to vulnerable applications
• Deploy endpoint detection and response (EDR) solutions capable of detecting stack buffer overflow exploitation attempts
• Use system integrity monitoring to detect unauthorized changes following potential exploitation

Monitoring Recommendations

• Enable detailed process auditing to capture command-line arguments for all executed processes
• Monitor for abnormal process behavior patterns such as unexpected memory access violations
• Implement logging for application crashes and core dumps related to NRSS
• Review system logs for indicators of privilege escalation or lateral movement following NRSS execution

How to Mitigate CVE-2016-20043

Immediate Actions Required

• Discontinue use of NRSS RSS Reader version 0.3.9-1 until a patched version is available
• Remove or restrict access to the NRSS binary on affected systems
• Limit local user access on systems where NRSS is installed to reduce attack surface
• Consider alternative RSS reader applications that are actively maintained and do not contain known vulnerabilities

Patch Information

No vendor patch information is currently available for this vulnerability. The NRSS project appears to be unmaintained based on the age of the vulnerable version. Organizations should evaluate alternative RSS reader solutions. For more information about the affected software, see the CodeZen NRSS project page.

Workarounds

• Remove the NRSS application from systems where it is not required
• If NRSS must be used, run it in a sandboxed environment or container to limit the impact of potential exploitation
• Implement application control policies to prevent execution of NRSS with untrusted input
• Deploy defense-in-depth measures such as ASLR (Address Space Layout Randomization) and DEP (Data Execution Prevention) at the OS level to make exploitation more difficult

# Remove NRSS from Debian-based systems
sudo apt-get remove nrss

# Alternatively, restrict execution permissions
sudo chmod 000 /usr/bin/nrss

# Verify NRSS is no longer accessible
which nrss