Myriad cancels 10 prediction markets after being hacked; affected users will receive automatic refunds.

on October 28, according to The Defiant, prediction market platform Myriad Markets confirmed that its internal admin wallet used for automatically creating and adjudicating certain markets was compromised. On October 26, the attacker exploited the wallet to manipulate the outcomes of 10 prediction markets and claim rewards, covering topics such as the IPOs of OpenAI and Anthropic, whether Base will issue a token in 2026, and the US midterm elections. Myriad subsequently revoked the wallet's admin privileges and declared the affected markets invalid.

The platform stated that the funds have been recovered, and it will automatically refund users holding positions on both sides based on the final prices of each outcome prior to the attack, deducting any rewards already claimed; no application is required from users. This vulnerability was attributed to a security issue in a third-party library used by a backend service several weeks ago. Although Myriad states that the attacker was unable to withdraw the funds, on-chain records show that the assets were transferred to other addresses, and their final whereabouts cannot be confirmed based on this alone.