---
id: "CVE-2026-11854"
kind: "vulnerability"
aliases: ["CVE-2026-11854"]
title: "Authentication endpoint error page reflects request data, enabling browser script injection"
severity: "medium"
cvss: 6.1
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["other", "web-apps"]
not_affected_if: []
published_at: "2026-10-28T20:17:22+00:00"
first_seen_at: "2026-10-28T20:35:10+00:00"
updated_at: "2026-10-28T20:36:15+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11854", "first_seen_at": "2026-10-28T20:35:10+00:00"}]
---

# Authentication endpoint error page reflects request data, enabling browser script injection

The authentication endpoint places unsanitized request data into its error message, so an attacker can inject script that runs in a victim's browser. Per the description, session cookies are httpOnly, so session hijacking is not possible, but the script can redirect users, alter the page, or read information shown on it.

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

## Timeline

- 2026-10-28T20:35:10+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-11854

## From the sources

The authentication endpoint generates an error message that includes reflected data directly from the request without sufficient sanitization or encoding. This allows an attacker to inject malicious scripts that can be executed in the context of a victim's browser.

Successful exploitation enables an attacker to perform actions within the user's browser, such as redirecting the user to a malicious website, modifying the web page's user interface, or retrieving information. However, due to the httpOnly flag on session-related cookies, session hijacking or similar attacks are not possible.

---

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