vulnerability / NVI-00011962 / Revision 2
Vikunja: Read-only project members can obtain any link share's access hash via the single-share read endpoint (v1 and v2) and escalate to the share's permission level
GitHub lists this reviewed advisory for code.vikunja.io/api. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
0.432%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.37515. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
code.vikunja.io/api
source listed<= 2.5.0
## Summary A user who has only read permission on a project can call the single link-share read endpoint and receive the share's `hash` field — the secret credential that the anonymous `POST /shares/{share}/auth` endpoint exchanges for a link-share JWT carrying the share's permission (read / read-write / admin). A read-only member can therefore mint a write- or admin-level token for the project and perform writes they are not entitled to, while their own user token is correctly refused. This is the remaining variant of the link-share hash disclosure class: GHSA-8hp8-9fhr-pfm9 fixed the list endpoint (ReadAll now requires project admin) but the single-read endpoint's gate was never aligned. Verified on Vikunja 2.5.0; the weak gate has existed since the endpoint, so earlier versions are likely affected too. ## Details Affected endpoints (both verified with a complete chain): - v1: `GET /api/v1/projects/{project}/shares/{share}` - v2: `GET /api/v2/projects/{project}/shares/{share}` Permission gate: `LinkSharing.CanRead` (`pkg/models/link_sharing_permissions.go`) delegates to `project.CanRead(s, a)` — i.e. any user with read access to the project passes. The response serializes th
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-qfwc-vx6f-3g6g ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-91985 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.