CVE-2026-33885: Statamic CMS Auth Bypass Vulnerability

CVE-2026-33885 Overview

CVE-2026-33885 is an Open Redirect vulnerability (CWE-601) affecting Statamic, a Laravel and Git powered content management system (CMS). The vulnerability exists in the external URL detection mechanism used for redirect validation on unauthenticated endpoints. This flaw allows attackers to bypass security controls and redirect users to external, potentially malicious URLs after legitimate actions such as form submissions and authentication flows.

Critical Impact

Attackers can exploit this vulnerability to redirect users to phishing sites or malicious domains after they complete trusted actions within the Statamic CMS, potentially leading to credential theft, malware distribution, or other social engineering attacks.

Affected Products

• Statamic CMS versions prior to 5.73.16
• Statamic CMS versions prior to 6.7.2

Discovery Timeline

• 2026-03-27 - CVE CVE-2026-33885 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2026-33885

Vulnerability Analysis

This Open Redirect vulnerability stems from insufficient validation of redirect URLs on unauthenticated endpoints within Statamic CMS. When users interact with forms or authentication flows, the application accepts a redirect parameter that is intended to return users to an internal page after completing the action. However, the external URL detection mechanism contains a bypass that allows attackers to craft malicious URLs that pass validation checks while still redirecting to external domains.

The vulnerability is particularly concerning because it affects unauthenticated endpoints, meaning attackers can craft malicious links without needing any prior access to the target Statamic installation. Users who trust the legitimate domain may not notice they are being redirected to an external site, making this an effective vector for phishing campaigns and credential harvesting.

Root Cause

The root cause lies in the flawed implementation of the external URL detection logic used for redirect validation. The validation routine fails to properly identify certain URL formats as external, allowing specially crafted URLs to bypass the intended security controls. This is a common pattern in Open Redirect vulnerabilities where edge cases in URL parsing are not adequately handled.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker crafts a malicious URL containing a Statamic form submission or authentication endpoint with a manipulated redirect parameter. When a victim clicks this link and completes the expected action (such as submitting a form or logging in), they are redirected to an attacker-controlled external domain instead of the intended internal page.

This vulnerability can be chained with phishing attacks where the attacker presents a fake login page on the external domain, capturing credentials as users believe they are still interacting with the legitimate Statamic-powered site. The trust established by the initial legitimate domain makes this attack particularly effective.

Detection Methods for CVE-2026-33885

Indicators of Compromise

• Unusual redirect patterns in web server access logs showing navigation from legitimate Statamic endpoints to external domains
• User reports of unexpected redirects after form submissions or login attempts
• Referrer headers showing traffic originating from your Statamic domain to suspicious external sites
• Authentication logs showing successful logins followed immediately by external redirects

Detection Strategies

• Monitor web application firewall (WAF) logs for requests containing redirect parameters pointing to external domains
• Implement URL inspection rules to flag requests with potentially malicious redirect targets
• Review access logs for patterns matching known Open Redirect exploitation techniques such as protocol-relative URLs or URL encoding tricks
• Deploy endpoint detection to identify suspicious redirect chains originating from Statamic endpoints

Monitoring Recommendations

• Configure alerting for redirect responses (HTTP 302/303/307) to external domains from your Statamic installation
• Implement content security policy (CSP) headers to limit allowed navigation targets
• Enable detailed logging for form submission and authentication endpoints to capture redirect parameter values

How to Mitigate CVE-2026-33885

Immediate Actions Required

• Upgrade Statamic CMS to version 5.73.16 or later for the 5.x branch
• Upgrade Statamic CMS to version 6.7.2 or later for the 6.x branch
• Review web server logs for any evidence of exploitation prior to patching
• Notify users if there is evidence that Open Redirect attacks may have been conducted against your installation

Patch Information

Statamic has released patches addressing this vulnerability in versions 5.73.16 and 6.7.2. The fix improves the external URL detection logic to properly identify and block attempts to redirect users to external domains through unauthenticated endpoints. Administrators should update to the latest patched version immediately.

For additional technical details and the official security advisory, refer to the GitHub Security Advisory for GHSA-7f74-7q5w-hj4r.

Workarounds

• Implement a web application firewall (WAF) rule to validate and sanitize redirect parameters on form submission and authentication endpoints
• Configure reverse proxy rules to strip or validate redirect parameters before they reach the Statamic application
• Restrict allowed redirect destinations to a whitelist of known internal paths until patching can be completed

# Example nginx rule to block external redirects on affected endpoints
# Add to your server block configuration
location ~* ^/(forms|login|auth) {
    # Block redirect parameters pointing to external URLs
    if ($arg_redirect ~* "^(https?:)?//[^/]") {
        return 403;
    }
    proxy_pass http://your_statamic_backend;
}