CVE-2025-71244: SPIP Open Redirect Vulnerability

CVE-2025-71244 Overview

CVE-2025-71244 is an Open Redirect vulnerability (CWE-601) affecting SPIP, a popular open-source content management system. The vulnerability exists in SPIP versions before 4.4.5 and 4.3.9, specifically within the login form when configured to operate in AJAX mode. An attacker can craft a malicious URL that, when visited by a victim, redirects them to an arbitrary external site after completing the login process.

This vulnerability is particularly concerning because it exploits the trust users place in legitimate login forms. While the attack requires user interaction and only affects sites where the login page has been customized to use AJAX mode, successful exploitation can facilitate phishing attacks, credential theft, or malware distribution by redirecting authenticated users to attacker-controlled domains.

Critical Impact

Attackers can redirect authenticated users to malicious external sites, enabling phishing attacks, credential harvesting, and social engineering campaigns that leverage trust in the legitimate SPIP site.

Affected Products

• SPIP versions prior to 4.4.5
• SPIP versions prior to 4.3.9
• SPIP installations with AJAX-enabled login pages

Discovery Timeline

• 2026-02-19 - CVE CVE-2025-71244 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2025-71244

Vulnerability Analysis

This Open Redirect vulnerability manifests when the SPIP login form is configured to operate in AJAX mode. The core issue stems from insufficient validation of redirect URLs passed through the login process. When a user successfully authenticates, the application processes a redirect parameter without adequately verifying that the destination URL belongs to the same origin or is on an approved allowlist.

The vulnerability does not affect default SPIP installations—it specifically targets deployments where administrators have customized the login page to function in AJAX mode. Notably, the SPIP security screen does not mitigate this vulnerability, meaning standard security configurations provide no protection against this attack vector.

From an exploitation perspective, the attack requires user interaction: the victim must click a malicious link and complete the login process. However, this user interaction requirement is offset by the social engineering potential, as users are more likely to trust redirect destinations that appear after authenticating to a legitimate site.

Root Cause

The root cause is improper validation of URL redirection parameters (CWE-601: URL Redirection to Untrusted Site) within the AJAX-based login handler. The login form accepts a redirect destination but fails to verify that this destination points to a trusted internal location, allowing attackers to specify external URLs that the application will honor after successful authentication.

Attack Vector

The attack leverages a network-based vector requiring no special privileges but necessitating user interaction. An attacker constructs a malicious URL containing the legitimate SPIP login endpoint with a crafted redirect parameter pointing to an attacker-controlled domain. The attack flow proceeds as follows:

1. The attacker crafts a URL to the target SPIP site's AJAX login form with a malicious redirect parameter
2. The victim receives the link through phishing email, social media, or other distribution channels
3. The victim clicks the link and is presented with the legitimate SPIP login page
4. Upon successful authentication, the user is redirected to the attacker's malicious site
5. The attacker's site can then harvest additional credentials, deploy malware, or conduct further social engineering

The vulnerability is particularly effective because the initial login page is legitimate, and users often do not scrutinize the destination after completing authentication.

Detection Methods for CVE-2025-71244

Indicators of Compromise

• HTTP requests to SPIP login endpoints containing redirect parameters with external domains
• Login form submissions followed by redirects to non-approved external URLs
• Unusual patterns of login activity followed by immediate session termination
• User reports of being redirected to unexpected sites after authentication

Detection Strategies

• Monitor web server access logs for login form requests containing suspicious redirect parameters pointing to external domains
• Implement URL pattern matching rules to flag login requests with redirect values that don't match the site's expected internal URL patterns
• Deploy web application firewall (WAF) rules to detect and block open redirect attempts in authentication workflows
• Configure SentinelOne Singularity to monitor for post-authentication redirects to untrusted destinations

Monitoring Recommendations

• Enable detailed logging for all authentication-related requests, including full URL parameters
• Set up alerts for login form submissions containing redirect parameters with external domain references
• Monitor for user complaints about unexpected redirections after logging in
• Track referrer headers to identify potential phishing campaigns distributing malicious links

How to Mitigate CVE-2025-71244

Immediate Actions Required

• Upgrade SPIP to version 4.4.5 or 4.3.9 or later immediately
• Review web server logs for any evidence of exploitation attempts targeting the login form
• If unable to patch immediately, disable AJAX mode on login pages as a temporary workaround
• Notify users about the potential for phishing attacks exploiting this vulnerability

Patch Information

SPIP has released security updates addressing this vulnerability. Organizations should upgrade to SPIP version 4.4.5 or 4.3.9 depending on their release branch. The SPIP Security Update Announcement provides detailed information about the fix. Additional technical details can be found in the SPIP Git Repository and the VulnCheck Advisory for SPIP.

Workarounds

• Disable AJAX mode on login pages if upgrading is not immediately possible
• Implement server-side URL validation to restrict redirect destinations to a predefined allowlist of trusted internal URLs
• Deploy WAF rules to filter requests containing external redirect parameters in login form submissions
• Educate users to verify URLs after authentication and report suspicious redirections

# Configuration example - Apache mod_rewrite rule to block external redirects in login forms
# Add to .htaccess or Apache configuration
RewriteEngine On
RewriteCond %{QUERY_STRING} (redirect|url|next)=https?://(?!yourdomain\.com) [NC]
RewriteRule ^spip\.php$ - [F,L]