CVE-2026-3216 in Canvas
Summary
by MITRE • 03/25/2026
Server-Side Request Forgery (SSRF) vulnerability in Drupal Drupal Canvas allows Server Side Request Forgery.This issue affects Drupal Canvas: from 0.0.0 before 1.1.1.
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Analysis
by VulDB Data Team • 03/31/2026
The vulnerability identified as CVE-2026-3216 represents a critical Server-Side Request Forgery flaw within the Drupal Canvas module, specifically impacting versions ranging from 0.0.0 through 1.1.0. This type of vulnerability falls under the Common Weakness Enumeration category CWE-918, which classifies server-side request forgery as a weakness where an application fails to properly validate or sanitize external input that controls the destination of server requests. The vulnerability stems from inadequate input validation mechanisms within the module's processing logic, allowing malicious actors to manipulate server-side operations through crafted requests that bypass normal access controls.
Drupal Canvas module operates as a content management framework component that processes external requests and integrates with various backend services. The SSRF vulnerability manifests when the module fails to properly validate or sanitize URLs provided by users or external sources, enabling attackers to redirect server requests to internal network resources that should remain inaccessible. This flaw specifically affects the module's handling of remote resource fetching operations, where user-supplied data is directly incorporated into server-side HTTP requests without proper sanitization or destination validation. The vulnerability's impact extends beyond simple data exfiltration as it can potentially enable attackers to access internal services, bypass firewall restrictions, or perform unauthorized operations against backend systems that are normally protected from external access.
The operational impact of this vulnerability is significant as it allows attackers to exploit the module's functionality to make unauthorized requests to internal systems that are typically protected by network segmentation. Attackers can leverage this vulnerability to enumerate internal services, access sensitive data stored on internal servers, or even escalate privileges by targeting authentication mechanisms within the internal network. The vulnerability particularly affects environments where Drupal Canvas is deployed with access to internal resources, as it enables attackers to bypass normal network security controls and directly interact with backend services that should remain isolated from external access. This creates a substantial risk for organizations that rely on Drupal Canvas for content management and may have internal systems that are not properly secured against internal network reconnaissance.
Security mitigations for this vulnerability should focus on immediate patching of the affected Drupal Canvas module to version 1.1.1 or later, which contains the necessary fixes to address the input validation flaws. Organizations should also implement network-level controls to restrict outbound connections from the web server, particularly to internal resources, and deploy web application firewalls that can detect and block suspicious request patterns. Input validation mechanisms should be strengthened to ensure that all external URLs are properly sanitized and validated against a whitelist of approved domains or IP addresses. Additionally, network segmentation strategies should be reviewed to ensure that internal services are not directly accessible from the web server, and access controls should be implemented to limit the scope of potential damage from successful exploitation attempts. The vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol: DNS, as attackers may leverage the SSRF capability to perform DNS resolution of internal resources, and T1566.001 for credential access through phishing with a malicious attachment, as the vulnerability could be exploited in conjunction with other attack vectors to gain deeper access to systems.