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CVE-2026-68581 high CVSS 8.1

Authorization Flaw in code.vikunja.io/api (CVE-2026-68581)

Summary

Vulnerability in code.vikunja.io/api (CVE-2026-68581). Confidential information can be exposed externally. Exploitable via GET /api/v1/users. Mitigation: upgrade to 2.4.0 or later.

Original description

The description as published by the source.

Executive Summary

Vikunja accepts both regular-user JSON Web Tokens (JWTs) and link-share JWTs through its generic authenticated API route group. A link-share JWT resolves to a models.LinkSharing principal whose GetID() method returns the numeric link_shares.id. The API-token management model then treats that generic numeric value as a users.id when it creates, lists, and deletes API tokens.

Because users.id and link_shares.id are independent positive sequences, a link share whose ID equals another user's ID is treated as that user by /api/v1/tokens. An ordinary authenticated attacker can obtain a target's numeric user ID through authenticated user search and create link shares on an attacker-writable project until the link-share sequence reaches that value. The colliding link-share principal can then list the target's API-token metadata, issue a new API token owned by the target, and delete target-owned API tokens. The newly issued token operates with attacker-selected valid API scopes under the target user's existing permissions.

I reviewed the vulnerable v2.3.0 source, the introducing commit, the stable tag history, and the inspected main revision directly. I also reviewed the recorded local HTTP and native-router validation results. Dynamic testing used only a local v2.3.0 Docker deployment with PostgreSQL and synthetic data; I did not test any public, hosted, or otherwise external instance. Historical tags were checked from source rather than exercis…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-68581 has been found in code.vikunja.io/api.
Attackers can target a specific entry point like GET /api/v1/users over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade code.vikunja.io/api to 2.4.0 or later.
If unsure, ask your IT team or search "code.vikunja.io/api CVE-2026-68581" on the vendor's site.

CVE-2026-68581 (code.vikunja.io/api) — CWE-863 / CVSS v3 8.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /api/v1/users / GET /api/v1/tokens / PUT /api/v1/tokens / DELETE /api/v1/tokens/
Patched: 2.4.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

Incorrect authorization (CWE-863) exists in code.vikunja.io/api. Attackers reach the vulnerable code path via GET /api/v1/users.

📍 Affected scope

Check the vendor advisory for the affected versions of code.vikunja.io/api. Attack surface: GET /api/v1/users / GET /api/v1/tokens / PUT /api/v1/tokens / DELETE /api/v1/tokens/.

🔥 Severity

Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 2.4.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual GET /api/v1/users requests with malformed payloads or SQL meta-characters. Run grep -r 'code.vikunja.io/api' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'code.vikunja.io/api' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で code.vikunja.io/api を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'GET /api/v1/users' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで GET /api/v1/users への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch 
    Upgrade code.vikunja.io/api to 2.4.0

    ステージング環境で 2.4.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify 
    Replay attack against GET /api/v1/users on staging to confirm patch closes the vector

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

go code.vikunja.io/api
[{"type":"SEMVER","events":[{"introduced":"0.22.0"},{"fixed":"2.4.0"}]}]

References

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