---
id: "CVE-2026-87861"
kind: "vulnerability"
aliases: ["CVE-2026-87861"]
title: "HTTP client: requests can reuse a connection authenticated for another origin"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["http-client", "negotiate-auth", "package"]
not_affected_if: []
published_at: "2026-10-20T21:17:20+00:00"
first_seen_at: "2026-10-23T21:57:21+00:00"
updated_at: "2026-10-25T05:04:30+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87861", "first_seen_at": "2026-10-23T21:57:21+00:00"}]
---

# HTTP client: requests can reuse a connection authenticated for another origin

When ambient user credentials are in use, an HTTP request aimed at one origin can be sent over a connection already authenticated via Negotiate for a different origin. The request then goes out without the credentials it was meant to carry, and the sources do not say which library or product is affected.

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

## Timeline

- 2026-10-23T21:57:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-87861

## From the sources

When using ambient user credentials, an HTTP request directed to one origin
may be dispatched over a connection previously authenticated via Negotiate for
a different origin, leaving the request's intended credentials unused.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_