Vikunja has File Size Limit Bypass via Vikunja Import

Exploitation

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

CVSS

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

EPSS

• CVE-2026-35602: 0.34% estimated exploitation activity in the next 30 days; percentile 27.26 (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.

Summary The Vikunja file import endpoint uses the attacker-controlled Size field from the JSON metadata inside the import zip instead of the actual decompressed file content length for the file size enforcement check. By setting Size to 0 in the JSON while including large compressed file entries in the zip, an attacker bypasses the configured maximum file size limit. Details During import, the JSON metadata from data.json inside the zip archive is deserialized into project structures. File content is read independently from the zip entries. When creating attachments, the code at pkg/modules/migration/createfromstructure.go:406 passes the attacker-controlled File.Size from the JSON: The file size enforcement check at pkg/files/files.go:118 then evaluates this attacker-controlled value: With Size set to 0 in the JSON, the comparison 0 20MB evaluates to false and the check passes. The actual file content (from the zip entry) can be up to 500MB per entry (the readZipEntry limit). Highly…

Published by the source

10 Apr 2026, 15:35 UTC

Last modified by the source

10 Apr 2026, 19:46 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qh78-rvg3-cv54

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# Patch Next advisory brief: CVE-2026-35602

Advisory: Vikunja has File Size Limit Bypass via Vikunja Import
IDs: CVE-2026-35602, GHSA-qh78-rvg3-cv54
Record: https://patchnext.com/advisories/cve-2026-35602 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code.vikunja.io/api 2.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected <= 2.2.2; fixed in 2.3.0

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

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## 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-qh78-rvg3-cv54 (GitHub-reviewed advisory GHSA-qh78-rvg3-cv54 lists affected ranges: Go code.vikunja.io/api >=0 <=2.2.2)

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