Myriad Markets voids 10 prediction markets on BNB Chain after internal wallet compromise and vows automatic refunds
On October 27, BNB Chain ecosystem prediction market platform Myriad Markets released an incident report saying that at 06:07 UTC on October 26, an attacker used a compromised internal wallet to force incorrect settlements on 10 AMM prediction markets on BNB Chain. The wallet was originally used to automatically create and settle some markets. The attacker first built positions on low-probability outcomes, then settled the markets in a way favorable to themselves and claimed payouts. Within minutes after receiving abnormal alerts, the team revoked the wallet’s administrative privileges and stopped the attack from continuing.
Myriad Markets said the attacker did not withdraw any funds. The attacker’s last large buy was not paid out, the team has revoked that position, and funds were transferred from the compromised wallet to a wallet controlled by the platform. The settlements of the 10 affected markets were invalid, and the platform will void them all. Each holder, whether long or short, will receive a fair-value refund based on “position size × the last price before the attack on that outcome”; any proceeds claimed from the forced settlement will be deducted from the refund. Users do not need to submit applications, and the money will be deposited into wallets automatically. The refunds will come from recovered funds and the market pool, and other markets were not affected.
The platform attributed the critical exposure to a vulnerability in an unnamed third-party library used by a backend service several weeks earlier, which exposed wallet keys. After the team carried out a security update last week, the attacker acted before the wallet rotation. The compromised wallet now has no permissions. The affected markets include: whether George Russell will win the 2026 F1 drivers' championship, whether Base will have a token generation event (TGE) in 2026, whether ETH will flip in CMC historical data in 2026, the next move in crude oil (up to $120 or down to $55), whether Democrats will sweep the 2026 U.S. midterm elections, gold prices (up to $4,900 or down to $3,700), whether ETH will be in the triple digits when Bitcoin falls below $50,000, whether ETH will be above $4,000 when Bitcoin rises to $100,000, whether Brian Armstrong will appear in the first episode of UpOnly, and who will IPO first, OpenAI or Anthropic.
Original sources:
Title: Incident Report: AMM Market Resolution Exploit (Oct 26) Publisher: MYRIAD (@MyriadMarkets) Publication date: 2026-10-27 URL: https://x.com/MyriadMarkets/status/2115117700779253890 Nature of source: first-party original post Verification status: the full post was read in this instance; verification date 2026-10-27. Supporting content: the attack began at 06:07 UTC on October 26, used a compromised internal wallet to force incorrect settlement of 10 BNB Chain AMM markets, had permissions revoked within minutes, the attacker did not withdraw funds, the last large buy was not paid out and was revoked, a third-party library vulnerability exposed the keys weeks earlier, the 10 markets were voided and the specific market names were listed, both sides are to be refunded at the attack-time last price (deducting already claimed proceeds), funds will be deposited automatically into wallets, the funds come from recovered assets and the market pool, and other markets were not affected.
Title: Myriad Voids 10 Prediction Markets After Admin-Wallet Compromise Publisher: The Defiant Publication date: 2026-10-27 URL: https://thedefiant.io/news/hacks/myriad-voids-10-prediction-markets-after-admin-wallet-compromise Nature of source: media report Verification status: only the visible portion of the page was read this time (article loading restricted); verification date 2026-10-27. Supporting content: reported that Myriad Markets voided 10 markets and promised to refund both sides at the pre-attack price while deducting already claimed proceeds (secondary reporting based on the platform’s incident report).
ABAB AI Insight
Myriad Markets is an AMM prediction market platform running on BNB Chain, and the creation and settlement of some of its markets are automated by an internal wallet. In this incident, the wallet private key was exposed several weeks earlier due to a vulnerability in a third-party library used by a backend service, and the attacker acted while the platform was carrying out a security update and before the wallet rotation. The attack path was to first build positions on low-probability outcomes, then use wallet privileges to force settlement and claim payouts, which was an abuse of privileges rather than a smart contract code vulnerability. The team revoked the privileges within minutes after receiving notice, and revoked the attacker’s last large buy that had not been paid out, transferring the funds to a wallet controlled by the platform.
On the capital and fund-flow side, the platform clearly stated that the attacker did not withdraw any funds and that the related assets were recovered. The refund will be calculated based on each outcome’s last price before the attack to determine position value, paid to both long and short holders, with any false proceeds already claimed deducted, and the funds will come from recovered funds and the market pool. This handling means affected holders are refunded based on the market state before the attack, rather than having their original cost guaranteed back or being settled at the post-forced-settlement price. Other markets continued to operate normally, indicating that the issue was limited to the 10 markets settled using that internal wallet.
Compared with similar prediction market incidents, some platforms have seen funds withdrawn or needed external assistance when admin keys or oracles were abused. In this case, Myriad Markets revoked privileges while the attack was still ongoing, confirmed that no funds were withdrawn, then voided the markets as a whole and promised automatic refunds. Unlike approaches that rely on users to file claims or lock up funds for a long time, the platform chose to deposit refunds automatically into wallets, reducing holders’ operational burden. However, a settlement wallet whose keys are exposed can affect the results of multiple markets in a short time, also showing the operational risk brought by concentrated privileges.
This incident reset the settlement results of 10 specific markets at Myriad Markets to a void status, and the automatic refund mechanism will restore holders to their pre-attack value level. The platform will subsequently need to complete the refund processing and correct the erroneous outcomes and profit-and-loss displays in the portfolio, while continuing to tighten security measures. Because the refunds depend on recovered funds and the market pool, and claimed proceeds must be deducted, the actual amount received will depend on each holder’s specific position and whether they already claimed. Other markets are unaffected, and the platform’s operational continuity has been maintained.
ABAB News · Cognitive laws
An automated settlement wallet’s key exposure can force the results of multiple prediction markets to be rewritten within minutes.
When the attack does not withdraw funds, the platform can void the markets as a whole and automatically refund both sides at the pre-attack price.
Key exposure caused by a third-party library vulnerability can still be exploited during the security-update window even if it happened weeks earlier.