Gettext

How out-of-bounds reads happen in C gettext .mo file parsers and how to fix it

A missing bounds check in the gettext `.mo` file parser inside `compose/asc-utils-l10n.c` allowed a malformed or truncated file to trigger out-of-bounds reads from heap memory. The vulnerability affected two distinct read sites — a `memcpy` of the full `AscLocaleGettextHeader` struct at line 131 and a 4-byte offset read at line 224 — neither of which validated that the source buffer was large enough. The fix adds explicit size checks before both reads, rejecting invalid files with a descriptive