Code: static bool check_allocations(ASS_Shaper *shaper, size_t new_size)
{
    if (new_size > shaper->n_glyphs) {
        if (!ASS_REALLOC_ARRAY(shaper->event_text, new_size) ||
            !ASS_REALLOC_ARRAY(shaper->ctypes, new_size) ||
             !ASS_REALLOC_ARRAY(shaper->emblevels, new_size) ||
             !ASS_REALLOC_ARRAY(shaper->cmap, new_size))
             return false;
     }
     return true;
 }

Vulnerability Type: DoS 
CWE ID: CWE-399
Summary: The check_allocations function in libass/ass_shaper.c in libass before 0.13.4 allows remote attackers to cause a denial of service (memory allocation failure) via unspecified vectors.
Commit Message: shaper: fix reallocation

Update the variable that tracks the allocated size. This potentially
improves performance and avoid some side effects, which lead to
undefined behavior in some cases.

Fixes fuzzer test case id:000051,sig:11,sync:fuzzer3,src:004221.