CVE-2026-105839 in libmikmod
Summary
by MITRE • 10/06/2026
libmikmod before 3.3.14 contains an integer overflow in the Oktalyzer loader OKT_doPBOD() that allows attackers to cause heap buffer overflow via crafted track counts. Attackers can supply an OKT module whose SLEN chunk wraps the 16-bit numtrk value, causing PBOD writes past allocated track pointers for crashes or code execution.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified in libmikmod versions prior to 3.3.14 represents a critical memory safety flaw located within the Oktalyzer module loader, specifically inside the OKT_doPBOD function. This component is responsible for parsing and processing data from MOD files that utilize the Oktalyzer format, a legacy sound file standard widely used in demoscene productions and retro gaming applications. The core technical deficiency stems from an integer overflow condition triggered during the validation of track count parameters embedded within the module's SLEN chunk. When the library processes these modules, it relies on 16-bit unsigned integers to determine the number of tracks allocated for memory management operations. However, due to insufficient boundary checks and improper handling of arithmetic operations involving this value, an attacker can supply a maliciously crafted OKT module where the numtrk field is manipulated to wrap around or exceed expected limits upon calculation.
This integer overflow directly leads to a heap buffer overflow condition that compromises the integrity of the application's memory space. Specifically, the flawed logic causes PBOD writes to occur past the boundaries of allocated track pointers. In normal operation, libmikmod allocates an array of pointers corresponding to the number of tracks declared in the module header. When the integer arithmetic fails due to the overflow, the calculated size or index used for these memory allocations becomes incorrect, typically resulting in a significantly smaller allocation than what is subsequently written by the parser. Consequently, subsequent write operations intended for track data spill over into adjacent heap regions, corrupting metadata structures such as malloc headers or neighboring objects. This corruption can destabilize the application's internal state and provide an attacker with arbitrary read and write primitives on the heap.
The operational impact of this vulnerability is severe, encompassing both denial of service and potential remote code execution depending on the context in which libmikmod is deployed. If a user opens or plays a maliciously crafted OKT module within an application linked against the vulnerable version of libmikmod, the immediate result is often a segmentation fault or crash due to memory access violations caused by the heap corruption. However, sophisticated attackers can leverage this heap buffer overflow to overwrite function pointers, exception handlers, or other control flow data structures located in adjacent memory regions. By carefully crafting the payload within the module file, an attacker could achieve arbitrary code execution with the privileges of the user running the application. This is particularly dangerous in scenarios where libmikmod processes untrusted audio files from external sources, such as music players, game engines, or web browsers that utilize plugin architectures to render multimedia content.
From a classification perspective, this vulnerability aligns with CWE-190 Integer Overflow or Wraparound and CWE-787 Out-of-bounds Write in the Common Weakness Enumeration taxonomy. The exploitation technique maps closely to ATT&CK Tactic TA0004 Privilege Escalation and Technique T1203 Exploitation for Client Execution, as it involves tricking a client application into processing malicious input that leads to code execution. Mitigation strategies must prioritize immediate software updates; organizations relying on libmikmod should upgrade to version 3.3.14 or later where the integer overflow in OKT_doPBOD has been patched with proper validation checks for track counts and buffer sizes. For applications unable to update immediately, input sanitization at the application layer is recommended, ensuring that any audio files processed are validated against expected format constraints before being passed to the library. Additionally, enabling modern memory protection mechanisms such as Address Space Layout Randomization (ASLR) and Heap Canaries can help mitigate the likelihood of successful exploitation by randomizing memory layouts and detecting heap corruption attempts respectively.