CVE-2026-126051 Node.js is vulnerable to a remotely triggerable uncaught exception in TLS servers via deferred handshake callbacks
Remote unauthenticated attackers can crash Node.js TLS servers using certain handshake callbacks by sending a client hello then padding and a FIN.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Harmful if only installed
- No
- Needs a specific call
- Yes
- Fix
- Available
What is CVE-2026-126051?
CVE-2026-126051 is a high-severity use after free vulnerability in nodejs node, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-476
Which versions are affected by CVE-2026-126051?
An affected version is only exploitable if your software calls SNICallback, OCSPRequest or server.addContext(). Many projects that include it are not exposed.
How do I fix CVE-2026-126051?
No fix published yet.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-126051 being exploited?
There is no known exploitation of CVE-2026-126051 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-126051, BELL-CVE-2026-126051, DEBIAN-CVE-2026-126051, GHSA-qggj-xpj2-fcw3, UBUNTU-CVE-2026-126051.