CVSS 4.0
9.3 criticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE-2026-56765
Critical (9.3). EPSS 0.5% chance of exploitation in the next 30 days. Fixed in code.vikunja.io/api 2.2.1.
Vikunja before 2.2.1 contains an authorization flaw where the LinkSharing.ReadAll endpoint exposes share hashes to users with read access, enabling permission escalation to admin-level shares. The GetTaskAttachment endpoint performs permission checks against user-supplied task IDs but fetches attachments by sequential ID without verifying ownership, allowing attackers to download and delete all file attachments across all projects instance-wide.
Severity
CVSS 3.1
9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 43% of CVEs (scores of 2026-10-31)
- CWE
- CWE-639
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-2pv8-4c52-mf8j | Go | code.vikunja.io/api | <2.2.1 | 2.2.1 |
| GO-2026-4855 | Go | code.vikunja.io/api | all versions | no fix published |
References
- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j
- https://www.vulncheck.com/advisories/vikunja-unauthenticated-instance-wide-data-breach-via-link-share-hash-disclosure-chained-with-cross-project-attachment-idor
- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j