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Vikunja EUVDEUVD-2026-78646

| CVE-2026-91970 HIGH
Allocation of Resources Without Limits or Throttling (CWE-770)
7.1
CVSS 4.0 · Vendor: VulnCheck
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource allocation limits
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
1 PoC candidate (unverified) Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv2 – Sep 15, 2026

An authenticated user of Vikunja before 2.6.0 can exhaust the memory of migration worker processes by launching a Planka import job that points at a server they control, which advertises a large number of individually size-compliant attachments. Because the migrator enforces per-file size limits but no aggregate memory budget, the worker is consumed and the instance becomes unavailable to every user on it. The flaw is rated 7.1 (CVSS 4.0, availability-only impact), requires low privileges but no user interaction, and no public exploit code or CISA KEV entry is associated with it at time of analysis; the vendor has released a fix in 2.6.0.

Earlier versions of this analysis (1)
v1 Sep 15, 2026 - 16:07 CVSS 6.5

Authenticated resource exhaustion in the Vikunja task-management platform before 2.6.0 lets any logged-in user cripple the entire instance by abusing the built-in Planka migration feature. Because the migrator enforces per-file size limits but no aggregate memory budget across a migration job, an attacker who points the importer at a server they control can advertise a large number of individually compliant attachments and drive worker memory to exhaustion, denying service to every user on the instance. The flaw is rated CVSS 6.5 (AV:N/AC:L/PR:L/UI:N, availability-only impact), no public exploit code or in-the-wild exploitation has been identified, and the vendor has released a fix in 2.6.0.

Affected VersionsENISA

vikunja 0 <2.6.0

Affected Packages

go code.vikunja.io/api fix: 2.6.0
euvd vikunja fix: 2.6.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in go, euvd

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 7.1 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (VulnCheck) · only source for this CVE.

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
None
Vulnerable system: Integrity
None
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

4
Analysis Updated
Sep 15, 2026 - 16:29 vuln.today
v2 - CVSS changed
Severity Changed
Sep 15, 2026 - 16:22 NVD
MEDIUM HIGH
CVSS changed
Sep 15, 2026 - 16:22 NVD
6.5 (MEDIUM) 7.1 (HIGH)
Patch available
Sep 15, 2026 - 16:03 EUVD

DescriptionCVE.org

Vikunja versions before 2.6.0 contain a resource exhaustion vulnerability in the Planka migrator that fails to enforce aggregate memory budgets during migration jobs. Authenticated attackers can submit migration requests pointing to attacker-controlled servers advertising numerous size-compliant attachments, exhausting worker memory and causing denial of service for all users.

Technical POC Analysis

CWE-770 (Allocation of Resources Without Limits or Throttling) in the Planka migrator of the Go module code.vikunja.io/api.

Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.

Latest POC

1 PoC candidate from github (unverified)

Sign in to open the public PoC links collected for this CVE.

Threat Intelligence Overview

EPSS Score
0.4%
Top 70% exploitable
Threat Intel
1
1 source
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 0.4%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

56
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

CVE-2026-68582 CRITICAL POC
9.3 Aug 02

Cross-tenant information disclosure in the self-hosted task manager Vikunja (0.24.0 through 2.3.0) lets a holder of any

CVE-2026-27575 CRITICAL POC
9.1 Feb 25

Weak password policy in Vikunja task management before 2.0.0 allows users to set trivially guessable passwords. PoC avai

CVE-2026-68581 HIGH POC
8.6 Aug 02

Principal type confusion in Vikunja (versions 0.22.0-2.3.0) allows an authenticated low-privilege attacker to fully cont

CVE-2026-27616 HIGH POC
7.3 Feb 25

Stored cross-site scripting (XSS) in Vikunja prior to version 2.0.0 allows authenticated attackers to steal authenticati

CVE-2026-27819 HIGH POC
7.2 Feb 25

Vikunja before version 2.0.0 contains a path traversal vulnerability in its backup restoration function that fails to va

CVE-2026-27116 MEDIUM POC
6.1 Feb 25

Vikunja is an open-source self-hosted task management platform. [CVSS 6.1 MEDIUM]

CVE-2026-28268 CRITICAL
9.8 Feb 27

Business logic vulnerability in Vikunja task management platform before 2.1.0 allows incomplete resource cleanup, potent

CVE-2026-56765 CRITICAL
9.3 Jul 10

Instance-wide data breach in Vikunja before 2.2.1 lets remote attackers exfiltrate and destroy every file attachment acr

CVE-2026-34727 CRITICAL
9.1 Apr 10

Vikunja's OIDC callback handler issues a full JWT to any successfully matched user without checking whether that account

CVE-2026-91973 HIGH POC
8.7 Sep 15

Vikunja instances before 2.6.0 expose CalDAV BasicAuth endpoints (/dav, /.well-known, and /feeds) that are not covered b

CVE-2026-91972 HIGH POC
8.7 Sep 15

Vikunja versions before 2.6.0 ship authentication endpoints under /api/v2 (login, register, password-reset, and OAuth to

CVE-2026-91985 HIGH POC
8.7 Sep 15

Vikunja prior to 2.6.0 leaks the secret hash that backs a project's link shares through its single-share read endpoint,

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