Vikunja: Stored XSS via Unsanitized SVG Attachment Upload Leads to Token Exposure

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-27616: 0.51% estimated exploitation activity in the next 30 days; percentile 43.75 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Details The application allows users to upload SVG files as task attachments. SVG is an XML-based format that supports JavaScript execution through elements such as <script tags or event handlers like onload. The application does not sanitize SVG content before storing it. When the uploaded SVG file is accessed via its direct URL, it is rendered inline in the browser under the application's origin. As a result, embedded JavaScript executes in the context of the authenticated user. Because the authentication token is stored in localStorage, it is accessible via JavaScript and can be retrieved by a malicious payload. Key security issues identified: No server-side sanitization of SVG content. SVG attachments are rendered inline instead of being forced as a download. Embedded JavaScript within SVG files is allowed to execute. Authentication tokens stored in localStorage are accessible to client-side scripts. PoC Tested Environment [ ] Application version: 1.1.0 [ ] Deployment type:…

Published by the source

25 Feb 2026, 22:40 UTC

Last modified by the source

27 Feb 2026, 21:52 UTC

Source last checked

26 Oct 2026, 15:14 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7jp5-298q-jg98

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# Patch Next advisory brief: CVE-2026-27616

Advisory: Vikunja: Stored XSS via Unsanitized SVG Attachment Upload Leads to Token Exposure
IDs: CVE-2026-27616, GHSA-7jp5-298q-jg98
Record: https://patchnext.com/advisories/cve-2026-27616 (revision 1, source checked 26 Oct 2026, 15:14 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected <= 0.24.6

## Suggested inspection (read-only)
- Go code.vikunja.io/api: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on code.vikunja.io/api.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7jp5-298q-jg98 (GitHub-reviewed advisory GHSA-7jp5-298q-jg98 lists affected ranges: Go code.vikunja.io/api >=0 <=0.24.6)

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