---
id: "CVE-2026-123871"
page: "https://infrastack.ai/live/CVE-2026-123871"
kind: "vulnerability"
aliases: ["CVE-2026-123871"]
title: "Node.js: proxy credentials leak into invalid-config error messages"
severity: "medium"
cvss: 6.2
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["ci", "logging", "node.js", "runtime", "self-hosted"]
not_affected_if: ["no-proxy-credentials", "proxy-not-configured"]
published_at: "2026-11-11T19:17:34+00:00"
first_seen_at: "2026-11-11T19:28:45+00:00"
updated_at: "2026-11-11T19:30:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123871", "first_seen_at": "2026-11-11T19:28:45+00:00"}]
exploit_sources: []
---

# Node.js: proxy credentials leak into invalid-config error messages

Link for people: https://infrastack.ai/live/CVE-2026-123871 (this .md is for agents)

Node.js writes proxy URLs, including any username and password, verbatim into ERR_PROXY_INVALID_CONFIG error messages in four code paths that the earlier redaction fix missed. Anyone who can read those logs, stderr output, or crash reports can recover the proxy credentials.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `node --version` and compare against the affected lines: 22.x, 24.x, 26.x.
- Check whether proxy settings in the environment (`HTTP_PROXY`, `HTTPS_PROXY`) include a username and password.
- Search application logs and crash reports for `ERR_PROXY_INVALID_CONFIG`.

## Timeline

- 2026-11-11T19:28:45+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123871

## From the sources

Node.js discloses proxy credentials in ERR_PROXY_INVALID_CONFIG error messages. CVE-2026-48615 established that a proxy credential must not appear in a Node.js error message and redacted the username and password from ProxyConfig.href, but that fix missed four error paths in the same subsystem, one of them inside the same constructor, which interpolate the raw proxy URL, credentials included, into an ERR_PROXY_INVALID_CONFIG message. The proxy URL comes from the environment, but the defect is the sink: a secret that Node.js redacts everywhere else is emitted verbatim into a much wider audience than the process environment, such as stderr, container logs, log aggregation, and crash reporting services. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

---

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