CVE-2016-20040 in Texas Instrument Emulator
Summary
by MITRE • 03/28/2026
TiEmu 3.03-nogdb+dfsg-3 contains a buffer overflow vulnerability in the ROM parameter handling that allows local attackers to crash the application or execute arbitrary code. Attackers can supply an oversized ROM parameter to the tiemu command-line interface to overflow the stack buffer and overwrite the instruction pointer with malicious addresses.
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Analysis
by VulDB Data Team • 05/06/2026
The vulnerability identified as CVE-2016-20040 represents a critical buffer overflow flaw within TiEmu 3.03-nogdb+dfsg-3, a popular emulator for Texas Instruments graphing calculators. This issue stems from inadequate input validation in the ROM parameter handling mechanism of the command-line interface, creating a security weakness that can be exploited by local attackers to compromise system integrity. The vulnerability specifically affects the application's ability to process oversized ROM parameters, which are used to load calculator firmware images for emulation purposes.
The technical implementation of this buffer overflow occurs through improper bounds checking during parameter processing within the tiemu application's stack-based memory management. When an attacker provides an oversized ROM parameter to the command-line interface, the application fails to validate the input length against the allocated buffer size, leading to stack memory corruption. This overflow directly impacts the instruction pointer register, allowing attackers to redirect program execution flow to malicious code locations. The vulnerability manifests as a classic stack-based buffer overflow scenario where the excessive input overwrites adjacent memory regions including return addresses and control flow data, enabling arbitrary code execution or application crash.
The operational impact of CVE-2016-20040 extends beyond simple application instability to encompass potential system compromise and unauthorized code execution. Local attackers with access to the system can leverage this vulnerability to execute malicious payloads with the privileges of the TiEmu process, potentially escalating their control over the affected system. The nature of the vulnerability means that any user who invokes the tiemu command with maliciously crafted ROM parameters could trigger the overflow condition, making it particularly dangerous in multi-user environments or when the application is used in automated contexts. This weakness directly violates the principle of input validation and memory safety, creating a pathway for privilege escalation and persistent system compromise.
Mitigation strategies for this vulnerability should focus on immediate input validation and memory management improvements within the TiEmu application. The most effective approach involves implementing strict bounds checking for all parameter inputs, particularly those related to ROM file handling, with proper size validation before buffer allocation. Additionally, employing stack protection mechanisms such as stack canaries and enabling address space layout randomization can significantly reduce exploitability. System administrators should consider restricting user access to the application when possible, and implementing application whitelisting controls to prevent unauthorized execution. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflow conditions in stack memory, and represents a clear violation of the ATT&CK technique T1059 Command and Scripting Interpreter, as it allows for arbitrary code execution through command-line interface manipulation. Regular security updates and patches should be implemented immediately upon availability to address this specific memory corruption vulnerability.