# 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.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **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 (`SNICallback`, `OCSPRequest`, `server.addContext()`)
- **Fix available:** Yes
- **Published:** 11 Nov 2026
- **Updated:** 11 Nov 2026
- **Also known as:** ALPINE-CVE-2026-126051, BELL-CVE-2026-126051, DEBIAN-CVE-2026-126051, GHSA-qggj-xpj2-fcw3, UBUNTU-CVE-2026-126051

## 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 (NULL Pointer Dereference)

## 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.

## Is CVE-2026-126051 being exploited?

There is no known exploitation of CVE-2026-126051 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-126051 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-126051 in the wild and no public exploit code.
Exposure: An affected version is only exploitable if your software calls SNICallback, OCSPRequest or server.addContext(). Many projects that include it are not exposed.

Affected product: nodejs node. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
   If an affected version is present, also search the code for calls to SNICallback, OCSPRequest or server.addContext() and report whether any exist.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-126051/ (Markdown: https://insights.sbomify.com/CVE-2026-126051/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-126051
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126051
- OSV: https://osv.dev/vulnerability/CVE-2026-126051

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-126051/
Summaries are generated and may contain mistakes; the official description above is the record.