Vikjuna: IDOR in Task Attachment ReadOne Allows Cross-Project File Access and Deletion

Exploitation

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

CVSS

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

EPSS

• CVE-2026-33678: 0.32% estimated exploitation activity in the next 30 days; percentile 24.80 (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 TaskAttachment.ReadOne() queries attachments by ID only (WHERE id = ?), ignoring the task ID from the URL path. The permission check in CanRead() validates access to the task specified in the URL, but ReadOne() loads a different attachment that may belong to a task in another project. This allows any authenticated user to download or delete any attachment in the system by providing their own accessible task ID with a target attachment ID. Attachment IDs are sequential integers, making enumeration trivial. Details The vulnerability is in pkg/models/taskattachment.go in the ReadOne method: The permission check in pkg/models/taskattachmentpermissions.go validates access to the URL task, not the attachment's actual task: The TaskAttachment struct binds URL parameters via struct tags (param:"task" and param:"attachment"): Attack flow for read (GET): The custom handler at pkg/routes/api/v1/taskattachment.go:156 calls CanRead (checks URL task) then ReadOne (loads attachment by ID…

Published by the source

25 Mar 2026, 21:17 UTC

Last modified by the source

25 Mar 2026, 21:17 UTC

Source last checked

26 Oct 2026, 15:18 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jfmm-mjcp-8wq2

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# Patch Next advisory brief: CVE-2026-33678

Advisory: Vikjuna: IDOR in Task Attachment ReadOne Allows Cross-Project File Access and Deletion
IDs: CVE-2026-33678, GHSA-jfmm-mjcp-8wq2
Record: https://patchnext.com/advisories/cve-2026-33678 (revision 1, source checked 26 Oct 2026, 15:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
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 2.2.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected <= 2.2.0; fixed in 2.2.1

## 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-jfmm-mjcp-8wq2 (GitHub-reviewed advisory GHSA-jfmm-mjcp-8wq2 lists affected ranges: Go code.vikunja.io/api >=0 <=2.2.0)

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