CVE
Node.js is vulnerable to a remotely triggerable uncaught exception in TLS servers via deferred handshake callbacks
Affects Node.js 24.x and 26.x TLS servers that use the SNICallback, OCSPRequest, newSession or resumeSession hook, or server.addContext(). Fixed in 24.22.3 and 26.13.1.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 24.22.3, 26.13.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 24.22.3, 26.13.1.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 42/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Node.js TLS servers that use certain handshake hooks, such as SNICallback, OCSPRequest, newSession, resumeSession, or addContext(), can be crashed remotely, without logging in, by a specially crafted connection. An attacker can make the server process terminate with an uncaught exception by sending a client hello followed by padding and a connection close.
Read the original 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.
Who should check
Teams running Node.js 24.x or 26.x TLS servers that use SNICallback, OCSPRequest, newSession, resumeSession or server.addContext().
Read the source excerpt
“This vulnerability affects all users in active release lines: 24.x, 26.x”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach17/20Affects Node.js (a widely deployed server, runtime, framework or database)
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 87 if added to CISA KEV
- Would score about 82 if CISA's SSVC rates exploitation active
- Would score about 47 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 24.22.3, 26.13.1.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126051 (Node.js is vulnerable to a remotely triggerable uncaught exception in TLS servers via deferred handshake callbacks), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-126051 (entry last updated 2026-11-11):
Affected:
- nodejs node: from 24.0.0, fixed in 24.22.3; from 25.0.0, fixed in 26.13.1
Fixed versions: 24.22.3, 26.13.1.
Conditions (all must be true for the bug to be hit):
- The TLS server uses the SNICallback, OCSPRequest, newSession or resumeSession hook, or server.addContext(). (source: https://nodejs.org/en/blog/vulnerability/november-2026-security-releases)
- Affected release lines are Node.js 24.x and 26.x. (source: https://nodejs.org/en/blog/vulnerability/november-2026-security-releases)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-126051 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126051 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://nodejs.org/en/blog/vulnerability/november-2026-security-releases
- https://cna.openjsf.org/security-advisories.html
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-126051
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126051"}.Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- nodejs node
From 24.0.0 · fixed in 24.22.3; From 25.0.0 · fixed in 26.13.1
Evidence 4
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 1
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126051
Is CVE-2026-126051 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The bug lets a remote, unauthenticated attacker terminate a Node.js server process through an uncaught exception raised in a deferred TLS handshake callback.Source: nodejs.org
Which versions are affected by CVE-2026-126051?
node: from 24.0.0 before 24.22.3; from 25.0.0 before 26.13.1.Source: cve.now feed data
Am I affected, and how do I check?
The listed ranges run from 24.0.0 to before 24.22.3 and from 25.0.0 to before 26.13.1, and only TLS servers that use the SNICallback, OCSPRequest, newSession or resumeSession hook, or server.addContext() are in scope. To check a setup, run node --version and search the server code for those hook names.Source: nodejs.org
How do I fix CVE-2026-126051?
Upgrade to Node.js 24.22.3 on the 24.x line or 26.13.1 on the 26.x line, which are the fixed releases listed for this vulnerability.Source: nodejs.org