CVE-2026-92775 in Wiki.js
Summary
by MITRE • 09/16/2026
Wiki.js through 2.5.314 contains a server-side request forgery vulnerability in the Image Prefetch renderer that fetches arbitrary URLs without protocol, host, or address validation. Attackers with page editing permissions can inject img elements with the prefetch-candidate class to make the server request internal services and cloud metadata endpoints, with responses returned to the attacker.
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Analysis
by VulDB Data Team • 09/16/2026
Wiki.js versions up through 2.5.314 are susceptible to a critical Server-Side Request Forgery vulnerability located within the Image Prefetch renderer component. This flaw stems from an insufficient validation of user-supplied input when processing image elements designated with the prefetch-candidate class. The underlying technical deficiency lies in the application's failure to enforce strict protocol, host, or address constraints on URLs provided by users during page editing operations. Consequently, the server-side rendering engine blindly processes these inputs and initiates HTTP requests to the specified destinations without performing any security checks to verify the legitimacy or safety of the target endpoint. This lack of input sanitization allows an attacker who possesses basic page editing permissions to manipulate the request destination entirely at will.
The operational impact of this vulnerability is significant, as it enables authenticated attackers with low-level privileges to pivot from a standard user role into performing internal network reconnaissance and data exfiltration. By injecting malicious img elements containing crafted URLs, an attacker can force the Wiki.js server to make requests to internal services that are not exposed to the public internet but remain accessible within the local network or container environment. Furthermore, this vulnerability facilitates access to cloud metadata endpoints, such as those found in AWS EC2 instance metadata service (IMDSv1) or similar providers like Azure and GCP. These endpoints often contain sensitive authentication credentials, temporary security tokens, and configuration details that can be harvested by an attacker if the server is running within a compromised cloud infrastructure. The responses from these internal requests are returned to the attacker through the application's response stream, effectively turning the Wiki.js instance into a proxy for accessing restricted resources.
From a classification perspective, this vulnerability aligns with CWE-918, which describes Server-Side Request Forgery (SSRF). The specific mechanism involves the use of client-side input to trigger server-side actions without proper validation, falling under the broader category of improper restriction of operations within the bounds of a memory buffer or network resource. In terms of adversary tactics, this behavior maps directly to ATT&CK technique T1598, specifically Phishing for Information from Cloud Infrastructure when targeting cloud metadata endpoints, and T1046, Network Service Discovery, when probing internal services. The vulnerability highlights a common misconfiguration in web applications where rendering engines trust user-provided URLs without verifying the destination's origin or type.
Mitigation strategies should focus on immediate patching to version 2.5.315 or later, which addresses this validation gap. In environments where upgrading is not immediately feasible, network-level controls such as firewall rules can be implemented to restrict outbound traffic from the Wiki.js server IP address to only known and necessary external domains. Additionally, implementing strict Content Security Policy headers may help mitigate some aspects of client-side manipulation, although they do not directly prevent SSRF at the server level. It is also recommended to enforce principle of least privilege by ensuring that users with page editing permissions have minimal access rights and are monitored for anomalous behavior. Regular security audits focusing on input validation in rendering components can further reduce the risk of similar vulnerabilities arising from other features within the application.