CVE-2026-56846

A flaw was found in Node.js's handling of HTTP/2. This vulnerability allows a remote attacker to bypass maxSessionMemory limits by sending specially crafted HTTP/2 retained header blocks. This can lead to memory exhaustion, resulting in a denial of service (DoS) for the affected system.

This Important flaw in Node.js HTTP/2 handling allows a remote attacker to bypass maxSessionMemory limits by sending specially crafted header blocks. This can lead to memory exhaustion and a denial of service for Node.js applications configured to use HTTP/2, without requiring authentication or user interaction.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, restrict network access to Node.js applications utilizing HTTP/2 to trusted clients only, by implementing firewall rules or network access controls. If HTTP/2 functionality is not essential for the application, consider disabling it in the Node.js configuration to prevent exploitation. Always ensure that any service restarts or reloads are performed carefully to avoid service disruption.