CVE-2026-91968
Received Received - Intake

Resource Exhaustion in Vikunja via Nested Task Filters

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: VulnCheck

Description
vikunja versions before 2.6.0 contain a resource exhaustion vulnerability in the task-filter endpoint that accepts deeply nested filter expressions without recursion depth limits. Authenticated attackers can supply thousands of nested parentheses in the filter query parameter to exhaust memory and terminate the API process.

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Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
CVE-2026-91968
EUVD
EUVD-2026-78644

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
vikunja vikunja From 2.5.0 (inc) to 2.6.0 (exc)
vikunja vikunja to 2.6.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-674 The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.

Attack-Flow Graph

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Executive Summary

This vulnerability is a resource exhaustion issue in Vikunja versions before 2.6.0. It occurs in the task-filter endpoint where attackers can send deeply nested filter expressions with thousands of parentheses in the filter query parameter. This causes the API to run out of memory and crash.

Detection Guidance

Monitor API process memory usage and look for excessive CPU consumption during filter operations. Check logs for unusually large or deeply nested filter queries in the task-filter endpoint. Use network traffic analysis tools to detect repeated requests with large payloads to the filter endpoint.

Impact Analysis

Authenticated attackers could exploit this to crash the Vikunja API service, leading to denial of service. This disrupts access to tasks and projects for all users relying on the system.

Mitigation Strategies

Upgrade Vikunja to version 2.6.0 or later to address the recursion depth issue. Implement rate limiting on the task-filter endpoint to prevent abuse. Add input validation to reject excessively large or deeply nested filter queries.

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