CVE-2025-53833: Cooking Up RCE with a Bad LaRecipe

You’ve carefully crafted your documentation, following the perfect recipe for clarity and user-friendliness. But what if a malicious actor could slip a dangerous ingredient into your mix, turning your helpful guide into a backdoor for complete server compromise? That's exactly the case with CVE-2025-53833, a critical Server-Side Template Injection (SSTI) vulnerability in the popular Laravel documentation package, LaRecipe.

Let's slice and dice this vulnerability to understand how a simple URL parameter could lead to a full-blown kitchen nightmare.

TL;DR / Executive Summary

• Vulnerability: Server-Side Template Injection (SSTI)
• CVE ID: CVE-2025-53833
• Affected Software: LaRecipe (binarytorch/larecipe) versions prior to v2.8.1.
• Impact: Unauthenticated attackers can achieve Remote Code Execution (RCE) by crafting a malicious URL. This allows them to execute arbitrary commands, read sensitive files (like your .env), and potentially take full control of the server.
• Severity: Critical (9.8)
• Remediation: The recipe for safety is simple: upgrade to LaRecipe version 2.8.1 or later immediately. Run composer update binarytorch/larecipe to patch your application.

Introduction: The Poisoned Cookbook

LaRecipe is a fantastic tool for developers. It provides an elegant way to create beautiful, code-driven documentation directly within a Laravel application. Think of it as a digital cookbook where you write the recipes (your documentation), and LaRecipe bakes them into a presentable format for your users.

The problem arises when the cookbook starts accepting "suggestions" from anyone who walks by. Server-Side Template Injection (SSTI) is a class of vulnerability where an attacker's input is improperly processed and executed as part of the server's page template.

Imagine your recipe template says, "Next, add {{ spice_name }}." You expect spice_name to be something like "oregano." But an attacker supplies system('burn_down_the_kitchen') as the spice. If the template engine is naive, it won't just print the text; it will dutifully execute the command. That's SSTI in a nutshell, and it's what makes CVE-2025-53833 so dangerous. For anyone running a public-facing site with a vulnerable version of LaRecipe, this isn't a theoretical risk—it's an open invitation for a takeover.

Technical Deep Dive: The Flaw in the Recipe

The root cause of this vulnerability is surprisingly small and located in a single line of code within the src/Models/Documentation.php file. Let's look at the function responsible for processing documentation content.

Root Cause Analysis

The vulnerable function, replaceLinks, is intended to correctly format internal links within the documentation. Here’s the problematic line:

// File: src/Models/Documentation.php (Vulnerable Version)

public static function replaceLinks($version, $content)
{
    // ... other replacements ...

    // The vulnerable line
    $content = str_replace('"#', '"'.request()->getRequestUri().'#', $content);

    return $content;
}

The function uses request()->getRequestUri() to get the current URL and prepend it to any anchor links (like href="#section"). The critical mistake is that getRequestUri() returns the entire URI, including the path and the query string.

The query string is the part of the URL after the ?, and it's completely controlled by the user.

So, if a user visits:
https://your-docs.com/page?{{7*7}}

The getRequestUri() function returns /page?{{7*7}}.

This value is then injected directly into the documentation's HTML content before it gets rendered by Laravel's Blade template engine. Blade sees the {{ 7*7 }} syntax, interprets it not as text but as code to be executed, and replaces it with 49.

This seemingly harmless feature—fixing links—becomes a powerful attack vector.

Attack Vectors and Business Impact

An unauthenticated attacker can exploit this by simply visiting a URL.

1. Information Disclosure: The attacker can leak sensitive environment variables.
   • Payload: ?{{config('app.key')}}
   • Impact: Leaks the application encryption key, which can be used to decrypt sensitive cookies and data.
2. File System Access: The attacker can read arbitrary files on the server that the web user has access to.
   • Payload: ?{{file_get_contents('../.env')}}
   • Impact: Steals database credentials, API keys, mail server passwords, and other secrets stored in the .env file.
3. Remote Code Execution (RCE): The ultimate goal. The attacker can execute arbitrary system commands.
   • Payload: ?{{system('whoami')}} or ?{{system('ls -la')}}
   • Impact: Full server compromise. The attacker can install malware, use the server in a botnet, steal all data, or pivot to other systems on the internal network.

Proof of Concept: A Taste of Danger

Here’s how an attacker would identify and exploit CVE-2025-53833.

Disclaimer: These examples are for educational purposes only. Do not attempt this on systems you do not own.

Step 1: Vulnerability Detection

The first step is to check if the server evaluates template syntax. An attacker would find a page rendered by LaRecipe and append a simple mathematical operation to the URL.

# Target a documentation page
curl "https://vulnerable-app.com/docs/1.0/installation?{{7*7}}"

If the response body contains 49 anywhere in the HTML where the link was rewritten, the application is vulnerable.

Step 2: Escalation to RCE

Once confirmed, the attacker can craft a payload to execute a command. Let's try to find out which user the web server is running as.

# Payload to execute the 'whoami' command
curl "https://vulnerable-app.com/docs/1.0/installation?{{system('whoami')}}"

If the server responds with www-data or a similar username, the attacker has confirmed RCE and can proceed with more destructive commands.

Mitigation and Remediation: The Antidote

Fortunately, fixing this vulnerability is straightforward.

Immediate Fix: Update Your Dependencies

The LaRecipe maintainers have released a patch in version v2.8.1. Update your project's dependencies by running:

composer update binarytorch/larecipe

Ensure your composer.json allows for this update. You should see binarytorch/larecipe updated to 2.8.1 or a newer version.

Patch Analysis: How the Fix Works

The fix is a perfect example of choosing the right tool for the job.

• Vulnerable Code:

  $content = str_replace('"#', '"'.request()->getRequestUri().'#', $content);
  

• Patched Code:

  $content = str_replace('"#', '"'.request()->getPathInfo().'#', $content);
  

The developers replaced request()->getRequestUri() with request()->getPathInfo().

Why does this work? getPathInfo() returns only the path component of the URL, completely ignoring the query string.

By using getPathInfo(), the user-controlled query string is no longer injected into the template. The injection point is eliminated, and the vulnerability is neutralized. It’s a simple, elegant, and effective fix.

Verification

After patching, repeat the detection PoC from earlier. This time, the server should treat the payload as literal text. Instead of seeing 49, you should see the raw string {{7*7}} in the page source.

Timeline of Events

• Discovery: The vulnerability was identified prior to July 14, 2025.
• Vendor Notification: The maintainers were notified and quickly developed a patch.
• Patch Availability: The fix was committed and released in version v2.8.1 on July 14, 2025.
• Public Disclosure: The vulnerability was publicly disclosed as CVE-2025-53833 on July 14, 2025.

Lessons Learned: Security Hygiene for Developers

This CVE serves as a powerful reminder of a few core security principles.

1. Never Trust User Input: This is the golden rule of security. Any data that originates from a user—whether it's from a form, a header, or a URL—must be treated as potentially malicious. Always sanitize, validate, and escape data appropriately for the context in which it will be used.
2. Understand Your Framework's Functions: The difference between getRequestUri() and getPathInfo() was the difference between a secure site and a compromised one. Deeply understanding the tools and frameworks you use is not optional; it's a requirement for building secure software.
3. Automate Dependency Scanning: This vulnerability would have been flagged by automated tools like GitHub's Dependabot or Snyk as soon as the advisory was published. Don't wait for a breach to find out you're using vulnerable code.

The Key Takeaway: Security isn't about a single, massive wall; it's about a series of small, correct decisions. Choosing the right function, sanitizing one more input, and keeping dependencies updated are the small hinges that swing big doors.

Stay safe, and happy (secure) coding!

References and Further Reading

• Official GitHub Advisory: GHSA-jv7x-xhv2-p5v2
• Patch Commit: View the fix on GitHub
• LaRecipe on Packagist: binarytorch/larecipe
• OWASP on SSTI: Server-Side Template Injection