Vikunja: Link-share token can enumerate users through the v2 API — GHSA-VFXW-3X8P-2VJR

Summary

### Summary A link-share token, the credential you hand out to let someone view a shared project, can call the v2 user-search endpoints, which it was never meant to reach. The v1 versions of the same endpoints correctly reject link-share tokens; the v2 versions don't. As a result, anyone with a share link can list every member of the shared project (and its parent projects), and can test whether any username exists…

Timeline

Published by source

2026-10-09

Risk context

• Reported severity or threat level: medium.
• Reported CVSS score: 5.3 out of 10.
• Reported EPSS value: 0.00306.
• Review exposure for the affected product or family: go: code.vikunja.io/api.

Product

go: code.vikunja.io/api

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-VFXW-3X8P-2VJR

Source

GitHub

Vendor

GitHub

Published by source

2026-10-09

Last source activity

2026-10-09

Additional identifiers

CVE-2026-91981

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.