Key Takeaways:
Ravencoin faces a possible three-day chain reorganization after a flaw in its KAWPOW mining algorithm let attackers mint blocks without doing the memory-intensive proof-of-work work.
Ravencoin fell 19.1 percent to about $0.00288 on Tuesday, with market capitalization shrinking to roughly $47.3 million and 24-hour volume near $11 million, according to CoinGecko data. The drop followed the project's Aug. 11 disclosure that a critical consensus vulnerability had been exploited since Aug. 7, allowing vulnerable nodes to accept invalid blocks beginning at height 4,487,776.
"2Miners and RavenMiner control a majority of network hash rate and are mining from the last unaffected block while excluding the exploited branch," the Ravencoin project said in its notice. The project warned that if that recovery chain becomes dominant, transactions confirmed after block 4,487,775 may disappear from the accepted history, with some returning to mempools and being mined again — though it said this is "not guaranteed."
The flaw sits in KAWPOW block header validation, according to an emergency release from mining pool 2Miners on Aug. 10. The KAWPOW header contains an nHeight field that was not checked against a block's actual position in the chain. By manipulating that value, an attacker could reach a validation path that skipped full proof-of-work verification and accepted a supplied mix hash without confirming genuine ProgPoW work. Blocks created through the flaw carried no genuine ProgPoW work and were "orders of magnitude cheaper" to produce than honest blocks at the same difficulty.
2Miners said exploitation continued from Aug. 7 through its Aug. 10 release. Between heights 4,489,527 and 4,491,615, it identified 96 affected blocks among 2,089 examined. A separate sample covering the period before Aug. 7 found no affected blocks, supporting the identified starting point. The pool also documented two effects seen on mainnet: affected nodes could fail after restarting, while nodes attempting to synchronize could encounter broken header sequences and fail to catch up.
2Miners released version 4.6.1.1-hf1, which rejects blocks whose declared header height differs from their actual chain position starting at 4,487,776. The patch also adds a checkpoint at 4,487,775 and rebuilds chain state when damaged index data prevents a node from continuing normally. The pool said the first restart can take several hours because the software replays about 4.49 million blocks and 28 million transactions while rebuilding chain state.
Ravencoin's official GitHub notes separately said there was not yet a core version patching both the KAWPOW problem and a different asset transfer quantity overflow bug. Maintainer Hans Schmidt recommended using the 2Miners code for the mining problem until a combined patch becomes available.
Upbit suspended Ravencoin deposits and withdrawals on Aug. 10, citing a network issue, before the project's broader warning, leaving trading available while transfers remain halted. Bitget also suspended RVN deposits and withdrawals for wallet maintenance beginning Aug. 10. Ravencoin advised exchanges to halt RVN deposits and withdrawals and told users to treat confirmations after block 4,487,775 as potentially reversible.
The incident is not the first for Ravencoin. In 2020, attackers exploited a flaw to create about 315 million unauthorized RVN, an excess token issuance bug, whereas the current vulnerability concerns proof-of-work validation and competing chain histories. The episode echoes an 18-block Monero reorganization in 2025 that invalidated previously confirmed transactions, illustrating why exchanges become cautious about transaction finality when proof-of-work networks develop competing histories.
The next milestones are a stable dominant chain, wider adoption of patched software and a combined upstream Ravencoin release. Until then, the project's guidance remains for exchanges to suspend transfers and for users not to rely on recent confirmations. Ravencoin stressed that its warning should not be interpreted as support for a rollback or any particular recovery plan.
This article is for informational purposes only and does not constitute investment advice.
