CVE-2026-49391 in Frappe
Summary
by MITRE • 08/07/2026
Frappe is a full-stack web application framework. Prior to 16.19.0 and 15.109.0, Data Import does not escape imported column headers before rendering previews and results, allowing an authenticated importer to persist script content that executes when another user views the import interface. This issue is fixed in versions 16.19.0 and 15.109.0.
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Analysis
by VulDB Data Team • 08/07/2026
This vulnerability exists within the Frappe web application framework where the Data Import functionality fails to properly escape column headers during preview and result rendering processes. The flaw represents a classic cross-site scripting vulnerability that occurs when user-supplied data containing malicious script content is not adequately sanitized before being rendered in the browser context. Attackers with authentication credentials can exploit this weakness by crafting import files containing malicious payloads within column headers, which then execute when other users view the import interface.
The technical implementation of this vulnerability stems from insufficient input validation and output escaping mechanisms within the Data Import module's rendering pipeline. When column headers are processed for display in the import preview, the framework fails to apply proper HTML escaping or sanitization techniques that would prevent script execution. This allows attackers to inject malicious javascript code, html tags, or other potentially harmful content directly into the column header fields. The vulnerability affects both the preview functionality and the final results display, creating multiple attack vectors for exploitation.
The operational impact of this vulnerability is significant as it enables authenticated attackers to perform persistent cross-site scripting attacks against other users within the same system. Once an attacker successfully uploads malicious column headers through the import process, any user who views the import interface will execute the embedded scripts in their browser context. This creates a potential for data exfiltration, session hijacking, or further exploitation of the victim's privileges. The vulnerability is particularly dangerous because it requires minimal user interaction beyond viewing the import interface, making it an effective vector for automated attacks.
The fix implemented in versions 16.19.0 and 15.109.0 addresses this issue through proper input sanitization and output escaping mechanisms that ensure column headers are properly encoded before rendering. The solution aligns with established security practices such as those outlined in CWE-79 which addresses cross-site scripting vulnerabilities, and follows ATT&CK technique T1213.002 for data from information repositories. Organizations should immediately upgrade to these patched versions and implement additional monitoring for suspicious import activities. Security measures including input validation, output encoding, and regular security assessments should be maintained to prevent similar vulnerabilities in other components of the application framework.
This vulnerability demonstrates the importance of proper sanitization in web applications where user-generated content is displayed, particularly in administrative interfaces where privileged users can perform operations that affect other system participants. The issue highlights the need for comprehensive security testing including dynamic analysis and input validation review to identify potential injection points within data processing pipelines and rendering components of web frameworks.