static void cs_mark(const char *cs_name, int subr)
{
    byte *data;
    int i, b, cs_len;
    int last_cmd = 0;
    integer a, a1, a2;
    unsigned short cr;
    static integer lastargOtherSubr3 = 3;       /* the argument of last call to
                                                   OtherSubrs[3] */
    cs_entry *ptr;
    cc_entry *cc;
    if (cs_name == NULL) {
        check_subr(subr);
        ptr = subr_tab + subr;
        if (!ptr->valid)
            return;
    } else {
        if (cs_notdef != NULL &&
            (cs_name == notdef || strcmp(cs_name, notdef) == 0))
            ptr = cs_notdef;
        else {
            for (ptr = cs_tab; ptr < cs_ptr; ptr++)
                if (strcmp(ptr->name, cs_name) == 0)
                    break;
            if (ptr == cs_ptr) {
                pdftex_warn("glyph `%s' undefined", cs_name);
                return;
            }
            if (ptr->name == notdef)
                cs_notdef = ptr;
        }
    }
    /* only marked CharString entries and invalid entries can be skipped;
       valid marked subrs must be parsed to keep the stack in sync */
    if (!ptr->valid || (ptr->used && cs_name != NULL))
        return;
    ptr->used = true;
    cr = 4330;
    cs_len = ptr->cslen;
    data = ptr->data + 4;
    for (i = 0; i < t1_lenIV; i++, cs_len--)
        cs_getchar();
    while (cs_len > 0) {
        --cs_len;
        b = cs_getchar();
        if (b >= 32) {
            if (b <= 246)
                a = b - 139;
            else if (b <= 250) {
                --cs_len;
                a = ((b - 247) << 8) + 108 + cs_getchar();
            } else if (b <= 254) {
                --cs_len;
                a = -((b - 251) << 8) - 108 - cs_getchar();
            } else {
                cs_len -= 4;
                a = (cs_getchar() & 0xff) << 24;
                a |= (cs_getchar() & 0xff) << 16;
                a |= (cs_getchar() & 0xff) << 8;
                a |= (cs_getchar() & 0xff) << 0;
                if (sizeof(integer) > 4 && (a & 0x80000000))
                    a |= ~0x7FFFFFFF;
            }
            cc_push(a);
        } else {
            if (b == CS_ESCAPE) {
                b = cs_getchar() + CS_1BYTE_MAX;
                cs_len--;
            }
            if (b >= CS_MAX) {
                cs_fail(cs_name, subr, "command value out of range: %i",
                        (int) b);
                goto cs_error;
            }
            cc = cc_tab + b;
            if (!cc->valid) {
                cs_fail(cs_name, subr, "command not valid: %i", (int) b);
                goto cs_error;
            }
            if (cc->bottom) {
                if (stack_ptr - cc_stack < cc->nargs)
                    cs_fail(cs_name, subr,
                            "less arguments on stack (%i) than required (%i)",
                            (int) (stack_ptr - cc_stack), (int) cc->nargs);
                else if (stack_ptr - cc_stack > cc->nargs)
                    cs_fail(cs_name, subr,
                            "more arguments on stack (%i) than required (%i)",
                            (int) (stack_ptr - cc_stack), (int) cc->nargs);
            }
            last_cmd = b;
            switch (cc - cc_tab) {
            case CS_CALLSUBR:
                a1 = cc_get(-1);
                cc_pop(1);
                mark_subr(a1);
                if (!subr_tab[a1].valid) {
                    cs_fail(cs_name, subr, "cannot call subr (%i)", (int) a1);
                    goto cs_error;
                }
                break;
            case CS_DIV:
                cc_pop(2);
                cc_push(0);
                break;
            case CS_CALLOTHERSUBR:
                if (cc_get(-1) == 3)
                    lastargOtherSubr3 = cc_get(-3);
                a1 = cc_get(-2) + 2;
                cc_pop(a1);
                break;
            case CS_POP:
                cc_push(lastargOtherSubr3);
                /* the only case when we care about the value being pushed onto
                   stack is when POP follows CALLOTHERSUBR (changing hints by
                   OtherSubrs[3])
                 */
                break;
            case CS_SEAC:
                a1 = cc_get(3);
                a2 = cc_get(4);
                cc_clear();
                mark_cs(standard_glyph_names[a1]);
                mark_cs(standard_glyph_names[a2]);
                break;
            default:
                if (cc->clear)
                    cc_clear();
            }
        }
    }
    if (cs_name == NULL && last_cmd != CS_RETURN) {
        pdftex_warn("last command in subr `%i' is not a RETURN; "
                    "I will add it now but please consider fixing the font",
                    (int) subr);
        append_cs_return(ptr);
    }
    return;
  cs_error:                    /* an error occured during parsing */
    cc_clear();
    ptr->valid = false;
    ptr->used = false;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.