CVE-2026-81848 in scrapling-fetch-mcp
Summary
by MITRE • 08/28/2026
A vulnerability was determined in cyberchitta scrapling-fetch-mcp up to 0.2.2. The impacted element is the function s_fetch_page/s_fetch_pattern of the file src/scrapling_fetch_mcp/_fetcher.py. Executing a manipulation can lead to server-side request forgery. The attack can be launched remotely. Upgrading to version 0.2.3 is sufficient to resolve this issue. This patch is called 9f6f34e92c55c3d95566ad9c62aca7327d24533a. Upgrading the affected component is advised.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified in cyberchitta scrapling-fetch-mcp versions up to 0.2.2 represents a critical server-side request forgery flaw within the core fetching mechanism of the application. This issue resides specifically in the s_fetch_page and s_fetch_pattern functions located in the src/scrapling_fetch_mcp/_fetcher.py file. As an MCP tool designed for web scraping, this component is inherently tasked with making network requests to external resources based on user-provided inputs or configuration patterns. The fundamental technical flaw lies in the insufficient validation of these input parameters before they are passed to the underlying HTTP client libraries. By failing to enforce strict allowlists for target domains or protocols, the application allows an attacker to supply arbitrary URLs that direct the server to make requests to unintended destinations. This lack of output control over network connections is a classic implementation error that transforms a utility function into a vector for malicious activity.
From an operational perspective, this vulnerability enables remote attackers to leverage the compromised service as a proxy or pivot point within the internal network architecture. Since the application runs on the server side and executes requests with its own permissions and network context, an attacker can manipulate it to access internal services that are not directly exposed to the public internet. This includes accessing local database interfaces, administrative panels of other applications running on localhost, or cloud metadata endpoints such as those found in AWS EC2 instances at 169.254.169.254. The ability to initiate these requests remotely means that no physical access or prior authentication within the internal network is required, significantly lowering the barrier for exploitation and increasing the potential blast radius of a successful attack.
The security implications align closely with CWE-918, which describes Server-Side Request Forgery (SSRF). This category of vulnerabilities occurs when a web application fetches a remote resource without validating the user-supplied URL. In this specific case, the absence of robust input sanitization allows for protocol manipulation and host bypass techniques. Furthermore, from an offensive security framework perspective, such behavior maps to ATT&CK technique T1571, which covers Non-Standard Ports or Protocols used in command and control scenarios, although here it is primarily utilized for reconnaissance and lateral movement rather than persistent access. The attacker can use the forged requests to scan internal networks, exfiltrate sensitive data from unprotected endpoints, or interact with backend APIs that trust local traffic by default.
To mitigate this risk immediately, organizations must upgrade cyberchitta scrapling-fetch-mcp to version 0.2.3 or later. This update incorporates specific patches designed to enforce stricter validation rules on the URLs processed by s_fetch_page and s_fetch_pattern. The patch identified as 9f6f34e92c55c3d95566ad9c62aca7327d24533a introduces checks that likely restrict allowed protocols to standard web standards such as HTTP and HTTPS while blocking dangerous schemes like file, gopher, or dict. Additionally, the update may implement domain allowlisting logic to ensure requests are only directed to pre-approved external domains. Until this upgrade is applied, administrators should consider implementing network-level controls such as firewall rules that restrict outbound connections from the host running the MCP server, thereby limiting the ability of any SSRF exploit to reach internal resources even if the application code remains vulnerable.