CVE-2026-91979
Received Received - Intake

Vikunja Archive Expansion DoS via Malicious Import

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: VulnCheck

Description
Vikunja before 2.6.0 fails to limit archive expansion during data import, allowing authenticated users to cause denial of service. Attackers can upload highly compressed files that expand to tens of gigabytes in memory and disk, exhausting server resources and crashing the instance.

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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-2026-91979
EUVD
EUVD-2026-78650

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
vikunja vikunja to 2.6.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-400 The product does not properly control the allocation and maintenance of a limited resource.

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Executive Summary

Vikunja before version 2.6.0 has a flaw where it does not restrict how much archive files can expand during data import. This allows authenticated users to upload compressed files that grow to extremely large sizes, consuming excessive server memory and disk space. This can lead to system crashes and denial of service by overwhelming resources.

Detection Guidance

Monitor server resource usage during file uploads or imports. Check for unusually high memory or disk consumption when users upload compressed archives. Look for processes consuming excessive CPU or disk I/O during import operations.

Impact Analysis

If you use Vikunja versions before 2.6.0, an attacker with access could upload a malicious archive file that expands to consume all available server resources. This may cause the application to slow down, crash, or become unavailable, disrupting normal operations for all users.

Mitigation Strategies

Upgrade Vikunja to version 2.6.0 or later to address the archive expansion issue. Implement size limits for uploaded files and archives. Monitor server resources closely during import operations to detect abnormal usage patterns.

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