CVE-2016-20048 in iSelect
Summary
by MITRE • 03/28/2026
iSelect 1.4.0-2+b1 contains a local buffer overflow vulnerability that allows local attackers to execute arbitrary code by supplying an oversized value to the -k/--key parameter. Attackers can craft a malicious argument containing a NOP sled, shellcode, and return address to overflow a 1024-byte stack buffer and gain code execution with user privileges.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/08/2026
The iSelect 1.4.0-2+b1 vulnerability represents a critical local buffer overflow flaw that demonstrates poor input validation and memory management practices within the application's command-line argument processing. This vulnerability specifically affects the -k/--key parameter handling mechanism, where the software fails to properly validate the length of user-supplied input before copying it into a fixed 1024-byte stack buffer. The flaw stems from a classic stack-based buffer overflow condition that occurs when the input exceeds the allocated buffer size, allowing subsequent memory writes to overwrite adjacent stack memory locations including return addresses and function pointers.
The technical exploitation of this vulnerability follows established patterns for stack-based buffer overflow attacks as outlined in the CWE-121 category for stack-based buffer overflow conditions. Attackers can construct malicious payloads that include a NOP sled to facilitate reliable code execution, followed by shellcode designed to perform the desired malicious actions, and conclude with a carefully crafted return address that redirects execution flow to the injected code. The vulnerability's local nature means that exploitation requires prior access to the target system, but the privilege escalation potential remains limited to the user context in which the application executes. This particular flaw violates fundamental security principles regarding input sanitization and memory safety, making it a prime target for exploitation by attackers who have already gained local access to a system.
The operational impact of this vulnerability extends beyond simple code execution capabilities as it provides attackers with a persistent foothold for further exploitation within the local environment. Once successfully exploited, the malicious code executes with the privileges of the user running the iSelect application, potentially allowing for privilege escalation attacks, data exfiltration, or system compromise. The vulnerability's presence in a command-line utility suggests that it could be leveraged in automated attack scenarios where attackers might use the application as a vector for more sophisticated attacks. The fact that this vulnerability exists in a widely used tool like iSelect creates additional risk as it may be present on numerous systems where attackers have already established initial access through other means.
Mitigation strategies for this vulnerability should focus on immediate code-level fixes including implementing proper input validation and bounds checking for all user-supplied parameters. The software should enforce strict limits on input length for the -k/--key parameter and reject oversized inputs before any memory operations occur. Additionally, developers should implement stack canary protections, address space layout randomization, and other exploit mitigation techniques to make successful exploitation more difficult even if similar vulnerabilities exist. The recommended approach aligns with defensive programming practices and follows the principle of least privilege where applications should never trust user input without proper validation. Organizations should also consider implementing runtime protections such as stack protection mechanisms and heap integrity checks as part of their overall security posture. The vulnerability's classification as a local privilege escalation vector emphasizes the need for comprehensive patch management and security monitoring to detect potential exploitation attempts.