CVE-2026-91971 Details
Description
Vikunja before 2.6.0 fails to apply pixel decode limits to avatar and project-background upload endpoints, allowing authenticated users to upload crafted images that decode to excessive pixel counts. Attackers can upload small images with extreme aspect ratios that consume significant CPU and memory during processing, causing denial of service through repeated or concurrent uploads.
A denial-of-service vulnerability has been identified in Vikunja versions prior to 2.6.0. The issue arises because the application fails to impose pixel decode limits on avatar and project-background upload endpoints. This oversight allows authenticated users to upload images that, while small in file size, have extreme aspect ratios and decode to excessive pixel counts. The processing of these crafted images consumes significant CPU and memory resources, leading to a denial-of-service condition. This vulnerability can be exploited through repeated or concurrent uploads of such images.
Users are advised to update to Vikunja version 2.6.0 or later, where this vulnerability has been addressed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 15, 2026CISA-ADP
Assessed Sep 21, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/go-vikunja/vikunja/security/advisories/GHSA-4vh2-39rq-rq8j | CISA-ADP | AdvisoryExploitTechnical AnalysisVendor |
| https://github.com/go-vikunja/vikunja/security/advisories/GHSA-4vh2-39rq-rq8j | [email protected] | AdvisoryExploitTechnical AnalysisVendor |
| https://www.vulncheck.com/advisories/vikunja-before-2.6.0-denial-of-service-via-avatar-upload | [email protected] | Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-400 | Uncontrolled Resource Consumption | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Vikunja | <= 2.5.0 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 21, 2026 | CVE Modified | CISA-ADP |
| Sep 15, 2026 | New CVE Received | [email protected] |