critical CVSS 10 EPSS 0.32%

CVE-2026-48930·Node.js vulnerability

A flaw in Node.js TLS hostname handling can cause Embedded-nul hostnames can lead to silent authority rebinding due to c-string truncation in resolver bindings. This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.

Severity
critical
Software
Node.js
Fixed in
18.20.4+dfsg-1~deb12u3
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 0.32% — higher than 24% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2026-48930 scores 10 on CVSS, so a successful attack would be serious — but at 0.32%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

Until: 18.20.4+dfsg-1~deb12u3

Fixed in: 18.20.4+dfsg-1~deb12u3

How to fix this CVE

Update Node.js to version 18.20.4+dfsg-1~deb12u3 or later to patch a critical TLS hostname validation flaw that allows attackers to bypass certificate authority checks through embedded null character exploitation. This vulnerability affects TLS connections across all supported Node.js release lines and requires immediate patching to prevent unauthorized certificate acceptance.

sudo dnf update nodejs

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your installed Node.js version with `node --version` and compare against the vulnerable range up to 18.20.3
  2. Step 2: Review TLS/SSL certificate validation logs in your application with `grep -i 'certificate\|hostname\|tls' /var/log/app.log | head -50`
  3. Step 3: Inspect network traffic captured during TLS handshakes for hostnames containing null bytes: `tcpdump -i any 'tcp port 443' -A | grep -P '\x00'`
  4. Step 4: Verify the patch by running `node --version` again and confirming version is 18.20.4 or higher, and restart all Node.js services with `sudo systemctl restart nodejs` or your application service

FAQ

What is CVE-2026-48930?

This is a critical TLS hostname validation bypass in Node.js caused by improper handling of embedded null characters in certificate hostnames, allowing attackers to silently redirect connections to unauthorized hosts due to C-string truncation in the resolver binding layer.

Is CVE-2026-48930 being actively exploited?

No, this vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities catalog and no public exploit code is available, though the critical CVSS 10.0 score indicates immediate patching is necessary.

What versions of Node.js are affected by CVE-2026-48930?

All versions up to and including 18.20.3, 22.x before the patched release, and 24.x and 26.x release lines are affected. The fix is available in Node.js 18.20.4+dfsg-1~deb12u3 and corresponding patches for later versions.

How do I check if my server is vulnerable to CVE-2026-48930?

Run `node --version` to get your installed version and cross-reference against the vulnerable ranges. If you're below 18.20.4, or running unpatched 22.x, 24.x, or 26.x releases, your system is vulnerable.

Does Defensia detect CVE-2026-48930?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Node.js is installed on a monitored server, CVE-2026-48930 will appear in your dashboard with remediation steps.

Related Node.js CVEs

CVE-2026-21636CVSS 10A flaw in Node.js's permission model allows Unix Domain Socket (UDS) connections to bypass network restrictions when `--permission` is enabled. Even without `--allow-net`, attacker-controlled inputs (such as URLs or socketPath options) can connect to arbitrary local sockets via net, tls, or undici/fetch. This breaks the intended security boundary of the permission model and enables access to privileged local services, potentially leading to privilege escalation, data exposure, or local code execution. * The issue affects users of the Node.js permission model on version v25. In the moment of this vulnerability, network permissions (`--allow-net`) are still in the experimental phase.
CVE-2025-55130CVSS 9.1A flaw in Node.js’s Permissions model allows attackers to bypass `--allow-fs-read` and `--allow-fs-write` restrictions using crafted relative symlink paths. By chaining directories and symlinks, a script granted access only to the current directory can escape the allowed path and read sensitive files. This breaks the expected isolation guarantees and enables arbitrary file read/write, leading to potential system compromise. This vulnerability affects users of the permission model on Node.js v20, v22, v24, and v25.
CVE-2026-48933CVSS 9A flaw in Node.js WebCrypto implementation can crash the process if the input of `subtle.encrypt()` is a multiple of 2GiB. This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.
CVE-2026-48937CVSS 9A flaw in Node.js HTTP/2 server API can cause servers to keep accepting data even after sending a `GOAWAY` frame. This vulnerability affects two supported release lines: **Node.js 22** and **Node.js 24**.
CVE-2026-48619CVSS 9A flaw in Node.js HTTP/2 client allows a server to send an unlimited number of ORIGIN frames, which could lead to an Out of Memory error on the client. This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.

References

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