CVE-2025-57292 in Todoist
Summary
by MITRE • 09/26/2025
Todoist v8484 contains a stored cross-site scripting (XSS) vulnerability in the avatar upload functionality. The application fails to properly validate the MIME type and sanitize image metadata.
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Analysis
by VulDB Data Team • 09/26/2025
The vulnerability identified as CVE-2025-57292 represents a critical stored cross-site scripting flaw within Todoist version 8484 that specifically targets the avatar upload functionality. This security weakness stems from inadequate input validation and sanitization processes that govern how the application handles user-uploaded image files. The flaw allows malicious actors to upload specially crafted avatar images that contain malicious script code, which then gets executed whenever the avatar is displayed to other users within the application interface. This stored XSS vulnerability creates a persistent threat vector that can affect multiple users over time, as the malicious content remains embedded within the application's data store until manually removed. The vulnerability directly violates security principles surrounding input validation and output sanitization, creating a pathway for attackers to execute arbitrary JavaScript code within the context of other users' browsers.
The technical implementation of this vulnerability occurs through the application's failure to properly validate MIME types and sanitize image metadata during the avatar upload process. When users upload avatar images, the system should verify that the uploaded file conforms to expected image formats such as jpeg, png, or gif while also ensuring that the file's metadata does not contain malicious code. However, Todoist's current implementation appears to accept various file types without adequate MIME type checking and fails to strip potentially dangerous metadata from image files that could contain embedded scripts or malicious payloads. This weakness aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities, and represents a classic example of insufficient input validation that allows malicious code to be stored and subsequently executed. The vulnerability operates at the intersection of file upload security and web application security, creating a persistent threat that can be exploited across multiple user sessions.
The operational impact of this stored XSS vulnerability extends beyond simple script execution, potentially enabling attackers to perform session hijacking, steal sensitive user information, manipulate application data, or redirect users to malicious websites. When an attacker successfully uploads a malicious avatar, any user who views that avatar within the Todoist interface becomes a victim of the stored XSS attack. This creates a propagation mechanism where a single compromised avatar can affect numerous users, potentially including administrators or other privileged accounts. The vulnerability can be exploited to access user credentials, personal information, or even modify task lists and project data, depending on the privileges of the affected users. This threat model aligns with ATT&CK technique T1566, which covers social engineering through malicious file uploads, and demonstrates how seemingly benign functionality can become a critical security risk when proper validation mechanisms are absent.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and sanitization measures within the avatar upload functionality. The application should enforce strict MIME type validation to only accept legitimate image formats while implementing robust metadata sanitization to remove any potentially dangerous content from uploaded files. Security controls should include automatic file type detection, content inspection, and the implementation of a whitelist approach for accepted file formats. Additionally, the application should employ proper output encoding when displaying user-uploaded content to prevent any residual malicious code from executing. Organizations using Todoist should also implement network-based protections such as web application firewalls and content security policies to add defense-in-depth layers. Regular security audits and vulnerability assessments should be conducted to identify similar weaknesses in other application components, while user education about suspicious file uploads can help reduce the risk of successful exploitation. The fix should align with industry standards including OWASP Top Ten security controls and NIST cybersecurity frameworks to ensure comprehensive protection against similar vulnerabilities in the future.