CVE-2026-126051: Node.js is vulnerable to a remotely triggerable uncaught exception in TLS servers via deferred handshake callbacks
A deferred-callback use-after-destroy in Node.js TLS server handshake handling allows a remote, unauthenticated attacker to terminate the server process. When a TLS server uses any of the SNICallback, OCSPRequest, newSession, or resumeSession hooks, or server.addContext(), the corresponding OpenSSL callbacks are deferred, and the deferred code does not handle the underlying socket being destroyed between scheduling and execution. By sending a client hello that reaches the vulnerable path (for example, no SNI together with an OCSP request) followed by padding and a socket FIN, an attacker makes OpenSSL deliver the client hello and the end-of-file in the same tick, so the socket is destroyed before the deferred callback runs and the process raises an uncaught exception instead of emitting an 'error' event. This vulnerability affects Node.js 26.x and 24.x.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 26.13.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 24.22.3
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
Which deployments are exposed?
Node.js 26.x and 24.x TLS server deployments are affected when they use SNICallback, OCSPRequest, newSession, resumeSession, or server.addContext(). The issue is in TLS server handshake handling.
Does exploitation require authentication or interaction from a legitimate user?
No. A remote, unauthenticated attacker can trigger the condition during the TLS handshake, without user interaction.
What is the operational impact of a successful attempt?
The Node.js server process terminates due to an uncaught exception rather than emitting an error event. The reported impact is denial of service; no confidentiality or integrity impact is specified.
How can an operator identify potentially affected application configurations?
Review TLS server code for use of SNICallback, OCSPRequest, newSession, resumeSession, or server.addContext(). A server using one of these mechanisms on Node.js 26.x or 24.x is within the affected configuration described.