CVE-2026-119144 in Frappe
Summary
by MITRE • 10/29/2026
Frappe Framework before 15.111.0 and 16.x before 16.21.0 contains a server-side template injection vulnerability because user-controlled message fields are rendered as templates without neutralization. An authenticated attacker holding a common operational role can inject template expressions that the server evaluates in an unrestricted context.
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Analysis
by VulDB Data Team • 10/29/2026
The Frappe framework, widely utilized for building web applications and enterprise resource planning systems, contains a critical server-side template injection vulnerability affecting versions prior to 15.111.0 and version 16.x prior to 16.21.0. This flaw stems from the improper handling of user-controlled input within message fields that are processed as templates by the backend rendering engine. In typical web application architectures, frameworks like Frappe use template engines such as Jinja2 or similar Python-based templating systems to dynamically generate content based on data provided by users or other system components. When these inputs are not adequately sanitized before being passed to the template parser, they allow for the injection of arbitrary code that is executed within the context of the server application.
The technical root cause lies in the failure to neutralize special characters and control sequences inherent in template syntax when processing message fields. An attacker who has authenticated into the system with a common operational role can craft specific inputs containing malicious template expressions. Because the framework renders these messages as templates without sufficient validation or escaping, the server interprets the injected content not merely as static text but as executable code directives. This allows the attacker to manipulate the rendering process and execute commands within the unrestricted context of the application server. The vulnerability is particularly severe because it does not require administrative privileges; access at a standard user level is sufficient to trigger the exploitation chain, significantly lowering the barrier for entry compared to vulnerabilities requiring high-privilege accounts.
From an operational perspective, this vulnerability poses a significant risk to data integrity and system availability. Successful exploitation can lead to remote code execution on the server hosting the Frappe application. This may result in unauthorized access to sensitive business data stored within the database, modification or deletion of critical records, and potential pivoting into internal network segments if the server is compromised further. The impact extends beyond immediate data loss, as it undermines the trust model of the authentication system by allowing lower-privileged users to perform actions typically reserved for administrators or backend processes. Organizations relying on Frappe for mission-critical operations face substantial exposure until this flaw is addressed in their deployment environments.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-94, which describes Improper Control of Generation of Code ('Code Injection'), and more specifically relates to server-side template injection where user input influences the structure or content of generated code without proper validation. In terms of attack tactics, this scenario maps directly to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, as the attacker leverages the application's own execution environment to run arbitrary commands. It also touches upon CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component, highlighting the failure to sanitize input before it is processed by downstream template engines.
Mitigation strategies must prioritize immediate patching and rigorous input validation practices. The primary remediation step is upgrading the Frappe framework to version 15.111.0 or later for the v15 branch, or version 16.21.0 or later for the v16 branch, where this specific rendering flaw has been corrected by developers through enhanced input sanitization and stricter template context isolation. For organizations unable to patch immediately due to operational constraints, implementing a Web Application Firewall (WAF) with rules designed to detect and block common template injection payloads can provide a temporary layer of defense. Additionally, enforcing the principle of least privilege ensures that even if an attacker gains access via this vector, their ability to cause widespread damage is limited by restricting what resources authenticated users at lower levels can interact with or modify within the application logic.