Braydon Fuller

**Name of the Vulnerable Software and Affected Versions** Bitcoin Core versions prior to 24.0.1 **Description** The issue allows remote attackers to cause a denial of service, resulting in a daemon crash, via a flood of low-difficulty header chains, also known as a "Chain Width Expansion" attack. This occurs because a node does not first verify that a presented chain has enough work before committing to store it. **Recommendations** For versions prior to 24.0.1, update to version 24.0.1 or later to resolve the issue. As a temporary workaround, consider implementing measures to limit the impact of a flood of low-difficulty header chains, such as restricting incoming connections or adjusting node configuration to require verification of work before storing chains.