CVE-2026-111917
Received Received - Intake

Improper Session Validation in Vikunja Allows Persistent WebSocket Access

Publication date: 2026-10-17

Last updated on: 2026-10-17

Assigner: VulnCheck

Description
Vikunja 2.3.0 before 2.7.0 contains an improper session validation vulnerability that allows attackers to keep WebSocket access after revocation because handleAuth never checks the JWT sid claim against the sessions table. Attackers holding a stolen access token can open or maintain connections to /api/v2/ws after session deletion or TOTP enrollment, continuing to receive the victim's notification.created pushes, including comment, task and project content.

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Meta Information

Published
2026-10-17
Last Modified
2026-10-17
Generated
2026-10-17
AI Q&A
2026-10-17
EPSS Evaluated
N/A
NVD
CVE-2026-111917
EUVD
EUVD-2026-103304

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
go-vikunja vikunja 2.3.0

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-613 According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."

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Executive Summary

Vikunja 2.3.0 through 2.6.9 has a vulnerability where WebSocket authentication does not validate if a session has been revoked. The handleAuth function fails to check the JWT session identifier (sid claim) against the sessions table, allowing attackers with a stolen token to maintain WebSocket connections even after the victim's session is deleted or TOTP enrollment is added.

Detection Guidance

Monitor WebSocket connections to /api/v2/ws for unauthorized sessions. Check for persistent connections after session revocation or TOTP enrollment. Inspect JWT tokens for missing or invalid sid claims during WebSocket authentication.

Impact Analysis

Attackers can use a stolen access token to keep receiving sensitive notifications like comments, tasks, and project content through WebSocket connections. This unauthorized access continues even after the victim revokes their session or enables TOTP, potentially exposing confidential data until the connection is manually closed.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive personal or health data, violating GDPR's data protection principles and HIPAA's security requirements for safeguarding protected health information. Non-compliance may result in legal penalties and reputational damage.

Mitigation Strategies

Upgrade Vikunja to version 2.7.0 or later. Implement server-side validation of the JWT sid claim during WebSocket authentication. Revoke all active sessions and enforce re-authentication after applying the fix.

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