---
id: "CVE-2026-91969"
kind: "vulnerability"
aliases: ["CVE-2026-91969", "GHSA-pqf9-h8g4-8gmh", "GO-2026-6746"]
title: "Vikunja: Unbounded CSV row cardinality permits API process termination in code.vikunja.io/api"
severity: "high"
cvss: 7.1
epss: 0.00348
exploited: false
status: "open"
category: "package"
products: [{"name": "code.vikunja.io/api", "fixed": [], "affected": "all versions", "ecosystem": "go"}, {"name": "code.vikunja.io/api", "fixed": ["2.6.0"], "affected": ">= 2.5.0, < 2.6.0", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["auth-required", "denial-of-service", "go", "package", "self-hosted", "vikunja"]
not_affected_if: ["auth-required", "default-config", "managed-hosting"]
published_at: "2026-09-15T16:17:53+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T21:46:44+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6746", "first_seen_at": "2026-10-23T19:13:08+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-91969", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91969", "first_seen_at": "2026-10-23T19:35:23+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-23T21:46:44+00:00"}]
---

# Vikunja: Unbounded CSV row cardinality permits API process termination in code.vikunja.io/api

Vikunja's authenticated CSV migration endpoint (POST /api/v2/migration/csv/migrate) caps upload bytes but not row count. It parses every row into memory and builds a task object for each. About 2 million one-cell rows (a ~4 MB request) got a 512 MiB API process OOM-killed. Any logged-in user, including a self-registered one if registration is open, can take the API down for everyone. VulnCheck rates it CVSS v4 7.1.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:code.vikunja.io/api affected all versions fixed ?
- go:code.vikunja.io/api affected >= 2.5.0, < 2.6.0 fixed 2.6.0

## How to check

Run 'vikunja version', or check the Docker image tag or the /api/v1/info version field. Versions >= 2.5.0 and < 2.6.0 are affected. The advisory says versions before 2.5.0 were not established as affected. Also check whether registration is enabled (service.enableregistration), since that lets anyone get an account.

## Fix

Upgrade Vikunja to v2.6.0 or later. The fix is in PR #3688, which adds configurable CSV import limits. Until you upgrade, restrict who can register or log in, or block POST /api/v2/migration/csv/migrate at the reverse proxy. Set a memory limit and a restart policy on the container.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6746
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-91969
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91969
- 2026-10-23T21:46:44+00:00 analyst — Read GHSA-pqf9-h8g4-8gmh, VulnCheck, GO-2026-6746, PR #3688. Endpoint POST /api/v2/migration/csv/migrate, requires authentication (any registered user). Fix in v2.6.0 (PR #3688 merged 2026-08-31). Advisory has a self-contained PoC (OOM of 512MiB container with 2M rows); no in-the-wild exploitation reported. Did not search social posts. Release v2.6.0 page not read directly.

## Documents

- [advisory] GHSA-pqf9-h8g4-8gmh: Unbounded CSV row cardinality https://github.com/go-vikunja/vikunja/security/advisories/GHSA-pqf9-h8g4-8gmh
- [describes] VulnCheck: vikunja before 2.6.0 CSV resource exhaustion https://www.vulncheck.com/advisories/vikunja-before-2.6.0-resource-exhaustion-via-csv-migration
- [fix] PR #3688 fix(security): harden authorization and resource limits https://github.com/go-vikunja/vikunja/pull/3688
- [mentions] GO-2026-6746 https://pkg.go.dev/vuln/GO-2026-6746

## From the sources

Vikunja: Unbounded CSV row cardinality permits API process termination in code.vikunja.io/api.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: code.vikunja.io/api from v2.5.0 before v2.6.0.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_