TI-2026-40929 Aliases CVE-2026-56765 GHSA-pg6g-jf8c-49p7

Authorization bypass in go-vikunja Vikunja

HIGH 81CWE-639Published 2026-07-10 · Updated 2026-07-10

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00512 43rd percentileScored 2026-11-07

Fix Fixed Vikunja (Vikunja): 2.2.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
go-vikunja	Vikunja	before 2.2.1	2.2.1	Patch available	CNA

Vikunja Vendorgo-vikunja Affected before 2.2.1 Fixed in 2.2.1 Patch available CNA

Remediation

Fix · CNA Vikunja (Vikunja) Fixed in 2.2.1

Timeline

2026-10-02 Threatist record created from CVE-2026-56765
2026-10-03 Alias added: GHSA-pg6g-jf8c-49p7

References

Advisory 1

GitHub Security Advisory (GHSA-2pv8-4c52-mf8j)

TI-2026-21967 Vijkunja has Weak Password Policy Combined with Persistent Sessions After Password Change CVSS 3.1CRITICAL 9.1
TI-2026-62115 Vikunja before 2.6.0 Privilege Escalation via Link Share Hash CVSS 4.0HIGH 8.7
TI-2026-62108 Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuth CVSS 4.0HIGH 8.7
TI-2026-62107 Vikunja before 2.6.0 Authentication Bypass via Unthrottled API CVSS 4.0HIGH 8.7
TI-2026-26971 Vikunja ahs a TOTP Two-Factor Authentication Bypass via OIDC Login Path CVSS 3.1CRITICAL 9.1
TI-2026-48322 Vikunja 0.24.0 Broken Object Level Authorization via Link-Share Token CVSS 4.0CRITICAL 9.3

See all 66 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences