I tried reporting this vulnerability to Yik Yak but got no response. So I'm releasing YakTrace publicly. It can deanonymize posts within a community, revealing authorship by user. Hopefully this gets Yik Yak's attention and pushes them to patch it.
GitHub - i3T4AN/Yaktrace: YakTrace reveals when multiple Yik Yak posts were made by the same anonymous account and organizes them into a local PDF dossier. Built on the sidechat.js API project.