CVE-2026-92449 in ThreadX
Summary
by MITRE • 10/20/2026
`_gx_binres_pixelmap_table_load()` in the GUIX binary resource (theme) loader indexes the pixelmap table with a value read verbatim from the resource file and never bounds it against the table size. A crafted theme drives a write of up to roughly 256 KB past the end of the table.
The overflowed buffer is allocated by GUIX itself, through `_gx_system_memory_allocator`, rather than supplied by the caller, so the loader corrupts its own arena. The public API `gx_binres_theme_load()` takes no size parameter, so no amount of caller diligence prevents this.
Reproduces in the shipped default configuration; `GX_BINARY_RESOURCE_SUPPORT` is enabled by default.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified within the GUIX binary resource loader constitutes a critical out-of-bounds write condition rooted in insufficient input validation during theme processing. Specifically, the function `_gx_binres_pixelmap_table_load()` retrieves an index value directly from the external theme file without performing any bounds checking against the actual size of the pixelmap table. This design flaw allows an attacker to supply a maliciously crafted resource file containing an excessively large index value. When processed by the vulnerable code path, this unchecked integer is used as an array offset, leading to memory writes that extend significantly beyond the allocated boundaries of the internal data structure. The severity of this issue is amplified by the magnitude of the overflow, which can write up to approximately 256 kilobytes past the end of the table, creating a substantial attack surface for exploitation and system instability.
From an architectural perspective, the impact is particularly severe because the memory being corrupted belongs to the GUIX internal heap rather than user-supplied buffers. The affected buffer is allocated via `_gx_system_memory_allocator`, meaning that the overflow corrupts the library's own memory arena. This type of corruption can lead to heap metadata damage, which may result in application crashes, unpredictable behavior during subsequent memory allocations, or potentially allow for arbitrary code execution if an attacker can carefully control the overwritten data and trigger specific allocator behaviors. Because the public API `gx_binres_theme_load()` does not accept a size parameter, there is no mechanism for caller-side validation to mitigate this risk. The responsibility for input sanitization lies entirely with the library implementation, yet it fails to enforce necessary constraints on data derived from untrusted sources.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) categories such as CWE-120 Buffer Overflow without bounds check and CWE-787 Out-of-bounds Write. In terms of offensive security frameworks, this flaw facilitates techniques associated with ATT&CK Tactic TA0004 Privilege Escalation or TA0005 Defense Evasion through heap exploitation patterns like Heap Spraying or Arbitrary Overwrite. The vulnerability is present in the shipped default configuration where `GX_BINARY_RESOURCE_SUPPORT` is enabled by default, meaning that any application utilizing GUIX themes without explicit mitigation patches is inherently vulnerable to remote code execution or denial of service attacks if it processes untrusted theme files.
Mitigation strategies must focus on implementing strict bounds checking within the `_gx_binres_pixelmap_table_load()` function before accessing array elements derived from external resources. Developers should ensure that all indices read from binary resource files are validated against the maximum valid index for the respective table structure. Additionally, integrating fuzzing tools into the development pipeline to test theme parsers can help identify similar parsing vulnerabilities across other GUIX components. Until a patch is applied, applications relying on this library should restrict theme loading to trusted sources only and consider implementing external validation layers that verify resource integrity before passing them to the vulnerable API functions.