Node.js HTTP/2 use-after-free leaks server memory to a peer

high severity · published 2026-11-11

A use-after-free during HTTP/2 stream teardown makes Node.js write freed heap memory to the socket instead of the intended response. A remote peer can therefore receive memory it should never see, such as data from unrelated connections.

Fixed in: 26.13.1

CVE: CVE-2026-123866

Source: NVD

Am I affected?

You are affected if the installed version is older than 26.13.1. Check the version you have and update to 26.13.1 or later. The fixed version is verified against a vendor or advisory source.

Get the fix

FixLane has a reviewed fix procedure for this incident: a read-only check first, then the fix. Ask the Telegram bot, or connect an AI agent to the FixLane MCP server and call get_fix_prompt with incident id 2543 and your operating system.