CVE-2026-25149: Qwik City Open Redirect Vulnerability

CVE-2026-25149 Overview

An Open Redirect vulnerability has been identified in Qwik City's default request handler middleware. Qwik is a performance-focused JavaScript framework designed for building fast, interactive web applications. Prior to version 1.19.0, the framework's request handler middleware allows remote attackers to redirect users to arbitrary protocol-relative URLs without proper validation.

This vulnerability (CWE-601: URL Redirection to Untrusted Site) enables attackers to craft malicious links that leverage the trusted domain's reputation while silently redirecting victims to attacker-controlled websites. Such attacks are particularly effective for phishing campaigns, credential harvesting, and distributing malware.

Critical Impact
Attackers can craft convincing phishing links that appear to originate from a trusted domain but redirect victims to malicious sites, potentially leading to credential theft, malware distribution, or other social engineering attacks.

Affected Products

Qwik framework versions prior to 1.19.0
Applications built with Qwik City using the default request handler middleware
Websites and web applications leveraging Qwik's routing capabilities

Discovery Timeline

2026-02-03 - CVE-2026-25149 published to NVD
2026-02-04 - Last updated in NVD database

Technical Details for CVE-2026-25149

Vulnerability Analysis

The vulnerability exists in Qwik City's default request handler middleware, which processes incoming HTTP requests and manages URL redirections. The core issue stems from insufficient validation of redirect target URLs, specifically failing to properly sanitize protocol-relative URLs (URLs that begin with //).

When a user accesses a crafted URL on a Qwik-powered application, the middleware processes the redirect without adequately verifying the destination. Protocol-relative URLs like //attacker.com are interpreted by browsers as using the same protocol as the current page, making them appear legitimate while actually pointing to an external domain.

This attack vector is network-accessible and requires no authentication or special privileges, making it trivial to exploit. While the direct security impact is limited to redirecting users, the downstream consequences can be significant in targeted phishing scenarios.

Root Cause

The root cause of this vulnerability is inadequate input validation in the request handler middleware. The code fails to properly distinguish between legitimate internal redirects and malicious external redirects disguised as protocol-relative URLs. The middleware does not implement sufficient checks to ensure redirect destinations are within the trusted domain boundary, allowing attackers to abuse the redirect functionality.

Attack Vector

Exploitation of this vulnerability follows a straightforward pattern. An attacker crafts a malicious URL targeting a Qwik-powered application that includes a protocol-relative redirect destination. When shared with potential victims, the URL appears legitimate because it uses the trusted domain in the visible portion. Upon clicking the link, the Qwik City middleware processes the request and redirects the user to the attacker-controlled destination.

The attack is particularly effective because:

The initial URL points to a legitimate, trusted domain
Email and security filters may not flag the link as malicious
Users have no visual indication of the redirect until it occurs
The protocol-relative format ensures compatibility across HTTP and HTTPS contexts

For detailed technical information about the vulnerability mechanism, refer to the GitHub Security Advisory GHSA-92j7-wgmg-f32m.

Detection Methods for CVE-2026-25149

Indicators of Compromise

Unusual redirect patterns in web server access logs showing protocol-relative URLs (URLs beginning with //)
HTTP referrer headers originating from your domain but leading to external suspicious destinations
User reports of being redirected to unexpected websites after clicking links to your application
Spike in outbound redirects to previously unseen domains

Detection Strategies

Monitor web application logs for redirect requests containing // patterns followed by external domain names
Implement URL pattern matching rules to detect protocol-relative redirect attempts in request parameters
Deploy web application firewall (WAF) rules to identify and alert on potential open redirect exploitation patterns
Analyze HTTP response codes (3xx) with external Location headers originating from the Qwik application

Monitoring Recommendations

Enable detailed logging for the Qwik City request handler middleware to capture all redirect operations
Set up alerts for unusual redirect patterns, particularly those targeting external domains
Monitor referrer traffic patterns for signs of phishing campaigns leveraging your domain
Track the ratio of internal vs. external redirects as a baseline for anomaly detection

How to Mitigate CVE-2026-25149

Immediate Actions Required

Upgrade Qwik framework to version 1.19.0 or later immediately
Audit existing Qwik applications for custom redirect implementations that may have similar vulnerabilities
Review web server and application logs for evidence of prior exploitation attempts
Notify users if any suspicious redirect activity was detected prior to patching

Patch Information

This vulnerability has been patched in Qwik version 1.19.0. The fix implements proper validation of redirect URLs to prevent protocol-relative and external URL redirections through the default request handler middleware.

The patch can be reviewed in the GitHub Commit Update which contains the security fix. Organizations should update their Qwik dependencies using their package manager to pull in the patched version.

Workarounds

If immediate upgrade is not possible, implement a custom middleware layer that validates all redirect destinations before they are processed
Configure a whitelist of allowed redirect destinations at the application or web server level
Use a reverse proxy or WAF to block requests containing suspicious protocol-relative URLs in redirect parameters
Implement Content Security Policy (CSP) headers with strict navigation directives as an additional defense layer

bash

# Upgrade Qwik to patched version
npm update qwik@1.19.0

# Verify installed version
npm list qwik