CVE-2026-56765 · Symaro Security Advisory

Description

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)

Base score	9.3
Severity	Critical
Version	CVSS 4.0
Vector	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Provided by	CNA

Weaknesses

CWE-639 — Authorization Bypass Through User-Controlled Key

Affected products

Vendor	Product	Versions
Vikunja	Vikunja	0 to <2.2.1; 2.2.1

References

https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j (vendor-advisory)
https://www.vulncheck.com/advisories/vikunja-unauthenticated-instance-wide-data-breach-via-link-share-hash-disclosure-chained-with-cross-project-attachment-idor (third-party-advisory)

Authoritative sources

This page is a snapshot. For the latest enrichment and updates, view the record on CVE.org or the NVD.

Generated from the official CVE List on 11 Jul 2026 07:02 UTC.