CVE-2016-20041
Buffer Overflow in Yasr -p Parameter Allows Code Execution
Publication date: 2026-03-28
Last updated on: 2026-03-28
Assigner: VulnCheck
Description
Description
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Meta Information
Affected Vendors & Products
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-22 | The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2016-20041 is a high-severity buffer overflow vulnerability in Yasr version 0.6.9-5. It occurs when a local attacker supplies an oversized argument to the command-line parameter "-p". This causes the application to overwrite the stack with junk data, shellcode, and a return address, which can lead to the application crashing or allow the attacker to execute arbitrary code.
The vulnerability arises from improper input validation and limitation of the pathname to a restricted directory, leading to a stack-based buffer overflow. An attacker can craft a payload that overwrites the stack and hijacks the program's control flow.
How can this vulnerability impact me? :
This vulnerability can have severe impacts including crashing the Yasr application, which affects availability, or allowing an attacker to execute arbitrary code with the privileges of the user running Yasr.
Since the exploit can lead to arbitrary code execution, it can result in unauthorized access, data manipulation, or local privilege escalation on the affected system.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by attempting to run the Yasr application version 0.6.9-5 with an oversized argument supplied to the -p parameter. A crafted payload containing junk data, shellcode, and a return address can trigger a crash or arbitrary code execution, indicating the presence of the vulnerability.
A test command to detect the vulnerability involves executing Yasr with a payload similar to the following pattern:
- yasr -p $(python -c 'print("A"*298 + "\x31\xc0\x50\x68//sh\x68/bin\x89\xe3\x50\x53\x89\xe1\x99\xb0\x0b\xcd\x80" + "\x90"*12 + "\xd2\xf3\xff\xbf")')
If the application crashes with a segmentation fault or behaves unexpectedly, it indicates the vulnerability is present.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include restricting local access to the Yasr application to trusted users only, as the vulnerability requires local attacker access.
Avoid running Yasr with untrusted input or scripts that supply arguments to the -p parameter.
Monitor for any unusual crashes or behavior of the Yasr application that might indicate exploitation attempts.
Apply any available patches or updates from the software maintainers that address this buffer overflow vulnerability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability in Yasr 0.6.9-5 is a local buffer overflow that allows arbitrary code execution, which can lead to a compromise of confidentiality, integrity, and availability of the affected system.
Such a compromise could potentially impact compliance with common standards and regulations like GDPR and HIPAA, which require protection of sensitive data and system integrity.
However, there is no specific information provided about direct effects on compliance or regulatory requirements in the available context.