CVE-2024-52920 is a denial of service vulnerability affecting Bitcoin Core versions before 0.20.0. The issue arises from improper handling of the GETDATA message, a protocol message used by Bitcoin nodes to request data such as blocks or transactions from peers. A remote attacker can send a specially crafted malformed GETDATA message that causes the node to enter an infinite loop, exhausting CPU resources and effectively causing a denial of service. This vulnerability falls under CWE-770, which concerns the allocation of resources without proper limits or throttling, leading to potential resource exhaustion. The vulnerability can be exploited remotely without any authentication or user interaction, making it relatively easy to trigger. The impact is limited to availability, as the infinite loop does not expose confidential data or allow modification of blockchain data. No known exploits have been reported in the wild as of the publication date. The CVSS v3.1 base score is 7.5, reflecting high severity due to network attack vector, low attack complexity, no privileges required, no user interaction, and high impact on availability. Since Bitcoin Core is widely used by cryptocurrency exchanges, wallet providers, miners, and other infrastructure operators, this vulnerability poses a significant risk to the stability of Bitcoin network nodes that have not been updated. The absence of patch links suggests that users should upgrade to version 0.20.0 or later, where this issue is resolved. Monitoring and filtering malformed GETDATA messages can help mitigate exploitation attempts until patches are applied.

The primary impact of CVE-2024-52920 is denial of service against Bitcoin Core nodes, which can disrupt the availability of critical cryptocurrency infrastructure. Organizations operating Bitcoin nodes, including exchanges, wallet services, miners, and blockchain analytics firms, may experience node crashes or unresponsiveness, leading to transaction delays, reduced network reliability, and potential financial losses. Disrupted nodes can also affect the overall Bitcoin network's health by reducing the number of active peers and slowing block propagation. Although the vulnerability does not compromise confidentiality or integrity, the availability impact can undermine trust in Bitcoin services and cause operational challenges. Large-scale exploitation could lead to widespread node outages, impacting global Bitcoin transaction processing and related services. The ease of exploitation and lack of required privileges increase the risk of opportunistic attacks by malicious actors or automated scanning tools.

1. Upgrade Bitcoin Core nodes to version 0.20.0 or later, where the vulnerability is fixed. 2. If immediate upgrade is not possible, implement network-level filtering to detect and block malformed GETDATA messages that do not conform to protocol specifications. 3. Employ rate limiting on incoming GETDATA requests to prevent resource exhaustion from excessive or malformed messages. 4. Monitor node logs and network traffic for unusual patterns or repeated malformed GETDATA messages indicative of exploitation attempts. 5. Use intrusion detection/prevention systems (IDS/IPS) with signatures tailored to detect this specific malformed message attack. 6. Maintain regular backups and ensure node redundancy to minimize service disruption if a node becomes unresponsive. 7. Participate in Bitcoin community security advisories to stay informed about patches and emerging threats related to Bitcoin Core.