CVE-2025-55751: OnboardLite CSRF Vulnerability

CVE-2025-55751 Overview

CVE-2025-55751 is an open redirect vulnerability [CWE-601] in HackUCF OnboardLite, a student organization lifecycle application developed for the University of Central Florida under the Influx Initiative. Attackers can craft URLs pointing to the trusted OnboardLite application that redirect users to arbitrary external destinations. This behavior enables phishing campaigns, credential theft, malware delivery, and abuse of the application's trust relationship with users. The maintainers addressed the issue by implementing JSON Web Token (JWT) signing for the redirect URL parameter. Any commit at or after hash 6cca19e contains the fix.

Critical Impact
Attackers can leverage the trusted OnboardLite domain to redirect victims to attacker-controlled sites, facilitating phishing and credential-theft campaigns against university users.

Affected Products

HackUCF OnboardLite versions prior to commit 6cca19e
Deployments built from main branch before the patch commit
Any fork or downstream deployment not rebased onto the fixed commit

Discovery Timeline

2025-08-20 - CVE-2025-55751 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-55751

Vulnerability Analysis

OnboardLite accepts a redirect_url parameter in authentication and navigation flows. Before the patch, the application did not cryptographically validate the parameter or restrict it to an allowlist of trusted destinations. An attacker crafts a link that appears to originate from the legitimate OnboardLite host but carries a redirect_url value pointing at an external attacker-controlled site.

When a victim clicks the link and completes the intended flow, the application forwards the browser to the attacker destination. Because the initial URL bears a trusted domain, users and email security controls are more likely to accept the request as legitimate. The downstream site can then present a spoofed login page, deliver malware, or continue further social engineering.

Root Cause

The root cause is missing integrity validation on a user-supplied redirect target, matching the CWE-601 URL Redirection to Untrusted Site pattern. The application trusted the parameter value directly without verifying that OnboardLite itself generated it.

Attack Vector

Exploitation requires user interaction. An attacker distributes a crafted OnboardLite URL through email, chat, or social media. When the victim visits the link, the server-side redirect delivers them to an attacker-chosen destination.

python

# Security patch in app/main.py - import signed redirect helpers
 from app.util.approve import Approve
 
 # Import middleware
-from app.util.auth_dependencies import Authentication, CurrentMember
+from app.util.auth_dependencies import Authentication, CurrentMember, verify_redirect_url, sign_redirect_url
 from app.util.database import get_session, init_db
 from app.util.discord import Discord

Source: GitHub Commit 6cca19e

python

# Security patch in app/util/auth_dependencies.py - add hashing support for signing
 import logging
 import time
 import uuid
+import hashlib
 from typing import Annotated, Optional
 
 from fastapi import Cookie, Depends, HTTPException, Request, status

Source: GitHub Commit 6cca19e

The patch introduces sign_redirect_url and verify_redirect_url helpers so the server signs the parameter it issues and rejects any redirect target lacking a valid signature.

Detection Methods for CVE-2025-55751

Indicators of Compromise

Inbound HTTP requests to OnboardLite routes containing redirect_url parameters that reference external hostnames
Referrer chains showing OnboardLite hosts issuing HTTP 302 responses to non-institutional domains
Phishing reports from users describing links that begin with the OnboardLite domain

Detection Strategies

Parse web server and reverse-proxy access logs for redirect_url query values and flag any destination outside an approved allowlist
Correlate outbound redirect events with newly registered or low-reputation domains through threat intelligence feeds
Alert on Location response headers where the host does not match the requesting OnboardLite instance

Monitoring Recommendations

Ingest OnboardLite application logs into a centralized logging pipeline for query and alerting on redirect abuse
Monitor email gateways and secure web gateways for OnboardLite links carrying suspicious redirect_url parameters
Track post-patch deployments to confirm the signed-parameter enforcement path is executing for every redirect

How to Mitigate CVE-2025-55751

Immediate Actions Required

Update OnboardLite to a build that includes commit 6cca19e or later and redeploy affected instances
Rotate any secrets exposed if phishing landing pages harvested credentials during the vulnerable window
Communicate to end users that redirect links from OnboardLite issued before the patch cannot be trusted

Patch Information

The fix is published in the HackUCF OnboardLite repository. Review the GitHub Security Advisory GHSA-p8c5-qp4c-qr2m and apply the changes from commit 6cca19e, which introduces sign_redirect_url and verify_redirect_url to enforce JWT-signed redirect targets.

Workarounds

Deploy a reverse-proxy rule that strips or validates the redirect_url parameter against an allowlist of institutional domains
Configure the web application firewall to block requests where redirect_url contains external hostnames or absolute URLs
Temporarily disable features that consume redirect_url until the patched build is rolled out

bash

# Example nginx rule to block external redirect targets pending patch deployment
location / {
    if ($arg_redirect_url ~* "^https?://(?!onboard\.hackucf\.org)") {
        return 403;
    }
    proxy_pass http://onboardlite_upstream;
}