According to CoinMeta, on August 11, it was disclosed that the Ravencoin project may face a three-day blockchain reorganization due to attackers exploiting a critical vulnerability in KAWPOW. This vulnerability allows attackers to create invalid blocks at a low cost without performing a complete proof of work. The first known invalid block appeared at block height 4487776, and the vulnerability has been exploited since August 7. The mining pool 2miners and ravenminer are building a chain that excludes the exploited branch. If this chain accumulates enough work to become dominant, Ravencoin warns that the network may experience a blockchain reorganization that could last about three days. Ravencoin has urged exchanges to suspend deposits and withdrawals of RVN until the network stabilizes.