# Brotli decoder flaw hits Node.js

Published: 2026-10-23 · Severity: severe
Canonical: https://vorant.io/reports/a2c393a2-c518-5a0d-8d2a-bcaaa25f6553/brotli-decoder-flaw-hits-node-js
Vorant's rating weighs the evidence in the report: confirmed exploitation, victims claimed, CVSS and EPSS, and how many sources agree. It rates the report, not your assets.

> A fixed out-of-bounds write bug in Google's Brotli decompression library, used by Node.js, could allow DoS, data leaks or remote code execution.

Source: advisories.ncsc.nl — https://advisories.ncsc.nl/2026/ncsc-2026-0453.html

## What to check

- Applies to: The 1 CVE named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation: CISA lists CVE-2026-111497 as exploited in the wild.

NCSC-NL published an advisory describing a vulnerability in Google's Brotli decompression library, which is bundled in Node.js and other software (including Debian packages). The flaw is an out-of-bounds write combined with an unchecked return value, and can be triggered remotely and without authentication by having the affected process decompress specially crafted Brotli-compressed data.

Successful exploitation could result in denial-of-service, disclosure of sensitive data from process memory, or arbitrary code execution with the privileges of the affected process. Google and the Node.js project have released patched versions addressing the issue. The advisory does not indicate any evidence of in-the-wild exploitation; this is a standard patch notification.

Defenders should identify any Node.js deployments, Debian packages, or other software bundling the Brotli library and apply the vendor-supplied updates. Because Brotli is widely embedded in web servers, CDNs, and language runtimes, affected software may extend beyond Node.js itself, so inventory of dependencies is recommended.

## Mentioned in this report

- Vulnerabilities: CVE-2026-111497 (KEV)

Source reporting: https://advisories.ncsc.nl/2026/ncsc-2026-0453.html

---

This is the free public brief from Vorant Threat Intelligence. When citing, attribute "Vorant" and link https://vorant.io/reports/a2c393a2-c518-5a0d-8d2a-bcaaa25f6553/brotli-decoder-flaw-hits-node-js.
In the app the same report carries live profiles of the CVEs it names. The paid plans add the security research and news reporting the free tier leaves out. Slack alerts on the vendors, sectors and countries a reader follows come with the paid plans too. A new account starts with a three-day trial, no card: https://vorant.io/signup