`_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.
