CVE-2026-62376 in Vikunja
Summary
by MITRE • 10/10/2026
Vikunja is an open-source self-hosted task management platform. Versions prior to 2.4.0 store password-reset, email-confirmation, and account-deletion tokens in the `user_tokens` table in plaintext. If an attacker gains read access to the database through a backup leak, misconfigured storage, or SQL-level exposure, they can immediately use pending tokens to take over user accounts without knowing passwords. Version 2.4.0 fixes the issue.
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Analysis
by VulDB Data Team • 10/10/2026
The vulnerability identified in Vikunja versions prior to 2.4.0 represents a critical failure in credential management and secure token storage practices within an open-source self-hosted task management platform. The core technical flaw lies in the database schema design, specifically within the user_tokens table where sensitive authentication artifacts such as password-reset tokens, email-confirmation codes, and account-deletion verification strings are persisted in plaintext rather than being hashed or encrypted using a robust cryptographic standard. This architectural decision fundamentally undermines the security model of these time-sensitive credentials, which rely on their secrecy to ensure that only the legitimate user can complete actions like resetting a forgotten password or confirming an email address change. By storing these tokens as clear text strings directly accessible via database queries, the system fails to implement defense-in-depth measures that would protect credential integrity even if the underlying data storage layer is compromised.
The operational impact of this vulnerability is severe because it effectively bypasses multi-factor authentication and strong password policies by allowing an attacker to hijack user sessions through administrative or recovery mechanisms rather than brute-forcing passwords. If a threat actor gains read access to the database, which can occur through various vectors such as leaked backups, misconfigured cloud storage buckets exposing database dumps, SQL injection vulnerabilities in other application components, or insider threats with direct database privileges, they obtain immediate and unrestricted ability to impersonate any user account that has an active token. This means that even if a user employs a highly complex password, the attacker can simply request a password reset for that user's email address, retrieve the generated plaintext token from the compromised database, and use it to set a new password or delete the account entirely. This leads to complete confidentiality loss of sensitive task data, potential integrity violations through unauthorized modifications, and availability issues if accounts are deleted maliciously.
From an industry standards perspective, this vulnerability is classified under CWE-256, which denotes the storage of passwords in a reversible format, although it specifically extends to other critical authentication tokens that serve similar functions for account recovery and verification. It also aligns with CWE-319 regarding cleartext transmission or storage of sensitive information, as well as CWE-798 if one considers the use of hardcoded or predictable values, though here the issue is primarily about lack of hashing rather than predictability. In terms of attack patterns, this flaw facilitates techniques associated with MITRE ATT&CK T1078, specifically Valid Accounts and Default Credentials, allowing attackers to establish persistence by taking over legitimate user identities without detection through traditional password-based intrusion methods. The vulnerability highlights a common pitfall in early-stage software development where convenience or simplicity is prioritized over security best practices for temporary tokens that should ideally be hashed using algorithms like bcrypt or Argon2 before storage, ensuring they cannot be reversed even if the database is exposed.
Mitigation strategies primarily involve upgrading to version 2.4.0 of Vikunja, which addresses this issue by implementing proper hashing mechanisms for these sensitive token fields in the user_tokens table. For organizations still running older versions where an immediate upgrade is not feasible due to compatibility constraints or deployment cycles, several compensating controls should be implemented immediately. These include restricting database access through strict network segmentation and firewall rules to ensure that only the application server can query the database, thereby reducing the attack surface for SQL-level exposure. Additionally, administrators must audit backup procedures to ensure they are encrypted at rest and stored in secure locations with restricted access permissions. Implementing regular vulnerability scans and penetration testing focused on authentication flows can help detect similar misconfigurations early. It is also recommended to enforce short expiration times for these tokens where possible, limiting the window of opportunity for an attacker who has gained read access to exploit them before they become invalid.