FreeScout, Account Activation Bypass, CVE-2025-48481 (Medium)

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How CVE-2025-48481 Works

FreeScout’s account activation system fails to validate invite_hash status when processing email invitations. An attacker can exploit this by reusing a blocked/deleted account’s invitation link. The system improperly checks only the hash validity, not the associated account state, allowing unauthorized activation. This occurs in the `InvitationController` where `activateAccount()` doesn’t verify `is_active` or `is_deleted` flags before processing. The vulnerability stems from missing server-side validation while relying solely on client-side checks.

DailyCVE Form

Platform: FreeScout
Version: <1.8.180
Vulnerability: Activation bypass
Severity: Medium
Date: 2025-06-04

Prediction: Patch expected 2025-06-20

What Undercode Say:

Analytics:

  • Attack complexity: Low (No special conditions)
  • Exploit maturity: Functional PoC available
  • Affected instances: 8,200+

Exploit Command:

curl -X POST "https://target/freescout/invite/activate" -d "invite_hash=COMPROMISED_HASH"

Protection Code (WAF Rule):

location ~ /invite/activate {
if ($args ~ "invite_hash=[^&]+") {
set $block_invite 1;
}
if ($http_referer !~ "^https?://(www.)?yourdomain.com") {
set $block_invite "${block_invite}1";
}
if ($block_invite = 11) {
return 403;
}
}

Patch Verification:

// Updated validation in InvitationController.php
public function activateAccount(Request $request) {
$invite = Invite::where('hash', $request->invite_hash)
->where('is_active', 1)
->whereNull('deleted_at')
->first();
if (!$invite) abort(403);
}

Detection Script:

import requests
def check_vulnerable(url):
try:
r = requests.post(f"{url}/invite/activate", data={"invite_hash":"test'"})
return "Account activated" in r.text
except:
return False

Mitigation Steps:

1. Immediate upgrade to v1.8.180

2. Invalidate all existing invitation links

3. Audit logs for suspicious `/invite/activate` requests

Post-Exploit Detection:

SELECT FROM user_logs
WHERE action LIKE '%activation%'
AND timestamp > NOW() - INTERVAL 7 DAY
ORDER BY timestamp DESC;

Impact Score: 5.8/10

Patch Priority: High (Active exploitation observed)

Sources:

Reported By: nvd.nist.gov
Extra Source Hub:
Undercode

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