CVE-2026-1406: BootDo Open Redirect Vulnerability

CVE-2026-1406 Overview

CVE-2026-1406 is an open redirect vulnerability discovered in lcg0124 BootDo, a Java-based web application framework. The vulnerability exists in the redirectToLogin function within the AccessControlFilter.java file, specifically in the Host Header Handler component. By manipulating the Hostname argument, an attacker can redirect users to malicious external websites, potentially facilitating phishing attacks or credential theft.

Critical Impact

Attackers can exploit this open redirect vulnerability to craft malicious URLs that appear legitimate, redirecting unsuspecting users to phishing sites or malware distribution pages. This can lead to credential theft, malware infection, or further social engineering attacks.

Affected Products

• lcg0124 BootDo up to commit 5ccd963c74058036b466e038cff37de4056c1600
• BootDo installations using the vulnerable AccessControlFilter component
• Applications utilizing the affected Host Header Handler functionality

Discovery Timeline

• 2026-01-25 - CVE CVE-2026-1406 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-1406

Vulnerability Analysis

This vulnerability falls under CWE-601 (URL Redirection to Untrusted Site, commonly known as Open Redirect). The flaw resides in the authentication flow of the BootDo application, specifically within the redirectToLogin function in AccessControlFilter.java. When handling login redirects, the application fails to properly validate the hostname parameter derived from the Host header before using it in redirect responses.

The vulnerability is network-accessible, requiring low privilege to exploit but also requiring some user interaction. When successfully exploited, attackers can manipulate the integrity of the redirect destination, causing users to be sent to attacker-controlled websites while believing they are navigating to a trusted domain.

Root Cause

The root cause of this vulnerability is improper validation of the Hostname argument within the Host Header Handler component. The redirectToLogin function accepts and processes the hostname value without adequate sanitization or verification against a whitelist of trusted domains. This allows attackers to inject arbitrary hostnames into the redirect URL, bypassing the intended authentication flow to redirect users to malicious external sites.

Attack Vector

The attack can be initiated remotely over the network. An attacker crafts a malicious URL containing a manipulated Host header or hostname parameter pointing to the vulnerable BootDo application. When a victim clicks this link or is redirected through it, the application processes the malicious hostname and generates a redirect response pointing to the attacker's controlled server.

The exploit has been publicly disclosed on GitHub, making it accessible to potential attackers. The attack flow typically involves:

1. Attacker identifies a BootDo installation with the vulnerable AccessControlFilter
2. Attacker crafts a URL with a malicious Hostname parameter
3. Victim is lured to click the malicious URL (via phishing email, social media, etc.)
4. The BootDo application redirects the victim to the attacker's malicious site
5. Attacker can harvest credentials, serve malware, or conduct further attacks

Detection Methods for CVE-2026-1406

Indicators of Compromise

• Unusual redirect URLs in web server access logs containing external hostnames
• Login redirects pointing to non-standard or suspicious domains
• User reports of being redirected to unexpected websites after authentication attempts
• Increased phishing reports from users who accessed legitimate application URLs

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests with suspicious Host header values
• Monitor access logs for redirect responses (HTTP 302/301) with external or untrusted destination URLs
• Deploy intrusion detection signatures to identify exploitation attempts targeting the Host header manipulation

Monitoring Recommendations

• Enable detailed logging for the AccessControlFilter component to capture all redirect events
• Set up alerts for redirect responses pointing to domains not in the trusted whitelist
• Regularly audit authentication flow logs for anomalous redirect patterns

How to Mitigate CVE-2026-1406

Immediate Actions Required

• Review and restrict the redirectToLogin function to only allow redirects to trusted internal domains
• Implement strict Host header validation using a whitelist approach
• Consider disabling the affected Host Header Handler functionality if not critical to operations
• Educate users about the risks of clicking suspicious links, even if they appear to originate from trusted domains

Patch Information

BootDo uses a rolling release model for delivering continuous updates. As a result, specific version information for patched releases is not available. Users should pull the latest commits from the official repository to obtain security fixes. Monitor the GitHub Issue Discussion and VulDB entry for updates on remediation guidance.

Workarounds

• Configure a reverse proxy or WAF to validate and sanitize Host headers before they reach the application
• Implement application-level hostname validation that restricts redirects to a predefined list of trusted domains
• Use security headers such as X-Frame-Options and Content-Security-Policy to limit the impact of potential redirect abuse

# Example WAF rule to block suspicious Host headers (ModSecurity)
SecRule REQUEST_HEADERS:Host "!@rx ^(www\.)?trusted-domain\.com$" \
    "id:1001,phase:1,deny,status:403,msg:'Invalid Host Header Detected'"