CVE-2026-111154 in libtimidity
Summary
by MITRE • 10/15/2026
libTiMidity through 0.2.8 contains a stack out-of-bounds write vulnerability in the SoundFont loader that allows attackers to corrupt stack memory via unchecked generator operators in parse_gen. Attackers can supply a crafted .sf2 file with out-of-range pgen/igen operator values to write chosen 16-bit values near the stack Layer object, causing crashes and stack memory corruption.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified within libTiMidity versions through 0.2.8 represents a critical security flaw located in the SoundFont loader component of the library. This specific issue is classified as a stack-based buffer overflow, technically categorized under CWE-121: Stack-Based Buffer Overflow. The root cause lies in the parse_gen function, which is responsible for parsing generator operators within SoundFont files. During this process, the software fails to adequately validate the range of operator values provided by the input file. Specifically, when processing .sf2 files, the application does not check whether the pgen and igen parameters fall within acceptable bounds before utilizing them as indices or offsets in memory operations. This lack of boundary checking allows an attacker who supplies a maliciously crafted SoundFont file to trigger out-of-bounds writes on the stack.
The operational impact of this vulnerability is severe due to its potential for arbitrary code execution and system instability. By exploiting the unchecked generator operators, an attacker can write specific 16-bit values to memory locations adjacent to the Stack Layer object. This action results in direct corruption of the stack memory, which typically holds critical data such as return addresses, saved frame pointers, and local variables. The immediate consequence is often a program crash or denial of service, disrupting any application relying on libTiMidity for audio synthesis. However, beyond simple crashes, this type of memory corruption poses a significant risk for more sophisticated attacks. If the attacker can control the data written to these adjacent stack locations, they may potentially overwrite function return addresses or other control flow mechanisms, thereby gaining the ability to execute arbitrary code with the privileges of the vulnerable application.
From an offensive security perspective, this vulnerability aligns with ATT&CK technique T1203: Exploitation for Client Execution, as it targets client-side applications that process multimedia files. It also relates to CWE-787: Out-of-bounds Write, highlighting the fundamental failure in memory safety checks. The exploitation vector is primarily remote or local depending on how the library is integrated into a host application. If libTiMidity is used by a media player or audio processing tool that opens user-supplied files, an attacker could distribute a malicious .sf2 file via phishing or compromised websites to trigger the vulnerability when the victim attempts to play the audio content.
Mitigation strategies for this vulnerability focus on both immediate patching and long-term defensive coding practices. The primary remediation is to upgrade libTiMidity to version 0.2.9 or later, where the developers have implemented proper bounds checking within the parse_gen function. For organizations unable to immediately update their dependencies, implementing input validation at the application layer can provide a temporary defense in depth. This involves sanitizing any SoundFont files before they are passed to the library's parsing routines, ensuring that all operator values conform to expected ranges defined by the SoundFont specification. Additionally, enabling compiler security features such as stack protectors and Address Sanitizer during development and testing phases can help detect similar memory corruption issues early in the software lifecycle. Regular code audits focusing on C/C++ projects are essential to identify other potential instances of unchecked array indexing or pointer arithmetic that could lead to similar vulnerabilities.