Cursed fanfiction is a type of fan - created writing that often contains very strange, disturbing, or unconventional elements. It might involve combining characters from different universes in really odd ways, or putting them in situations that are completely against their normal character traits. For example, making a cute and friendly cartoon character into a villain in a very dark and twisted story.
The origin of the cursed sword could be from an ancient and evil clan. Maybe they used dark magic to create it, and it was lost over time until Naruto discovers it by chance. For example, it could have been buried in a forgotten tomb that Naruto stumbles upon during a mission.
In most cases, reading fanfiction is legal as long as it is for personal enjoyment and not used for commercial purposes without permission. Fanfiction is a form of creative expression by fans, and as long as it doesn't violate any major copyright laws in terms of mass distribution or claiming the work as original, it's okay to read.
It could be that Harry breaks the cursed fanfiction through his strong will and determination. He refuses to be controlled by the curse within the fanfiction and his inner strength somehow shatters the curse. For example, if the curse is trying to manipulate his thoughts, he resists and in the process breaks it. Also, he might get help from his friends. They could combine their powers or knowledge to find a way to break the curse, like Hermione's research skills helping to figure out the nature of the curse and Ron's loyalty giving Harry the extra boost he needs.
Another possibility is an ancient evil that has been awakened. This entity might see Hermione as a threat because of her potential power. So it curses her to stop her from growing stronger. In this case, the antagonist would be very powerful and mysterious, and Hermione and her friends would have to do a lot of research and exploration to find a way to defeat it.
One common theme is the struggle against the curse. Hermione, being a strong - willed character, is often shown fighting to break free from the curse's hold. Another theme is the impact on her relationships. For example, her friendship with Harry and Ron might be strained as she tries to deal with the curse.
Hogwarts is a magical school, not a sentient being that can read. But if we consider the idea in a more metaphorical sense, within the world of fanfiction, we could imagine that some of the students at Hogwarts might be interested in 'The Cursed Child' fanfiction. They might read it to explore different interpretations of the events and characters they know so well. But in the context of the original series, there's no such indication.
It could be considered cursed because people who enter it often go missing. Maybe there are some dangerous and mysterious creatures living in there that prey on humans.
Perhaps it was a curse misfired. In the wizarding world, there are many powerful spells being cast all the time. Malfoy could have been in the wrong place at the wrong time. Maybe a curse that was meant for someone else, or a dark magic experiment gone wrong in the vicinity of Malfoy ended up cursing him. And also, considering his status as a pure - blood wizard, there could be some old family feuds or grudges from other pure - blood families that led to the curse.