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CVE-2026-91968 medium CVSS 6.5

Vulnerability in code.vikunja.io/api (CVE-2026-91968)

Summary

Vulnerability in code.vikunja.io/api (CVE-2026-91968). Risk of unauthorized operations or information disclosure. Exploitable via GET /api/v2/projects/{project}/tasks. Mitigation: upgrade to 2.6.0 or later.

Original description

The description as published by the source.

Unbounded nested task-filter recursion permits API process termination

Summary

Authenticated task-list routes accept a filter expression without a length or nesting-depth bound, preprocess it, parse it recursively through fexpr, and recursively convert the resulting expression tree. A syntactically valid deeply nested expression well below the HTTP request-size ceiling exhausts memory and kills the API process.

Impact and affected scope

  • Type: Resource Exhaustion Recursive Parser
  • Affected component: GET /api/v2/projects/{project}/tasks?filter=; Other authenticated task-collection entrypoints that share getTaskFiltersFromFilterString
  • Preconditions: A low-privileged authenticated user supplies thousands of balanced parentheses around a valid task predicate in the filter query parameter.
  • Verified revision: 349cd5adbcc831ef08b08e6c9c6d627603c39606 on 28 August 2026
  • Affected release range: = 2.5.0; broader historical range not established and maintainer confirmation requested

A single low-privileged network request can terminate the API process and deny service to all users.

Technical details

The server preprocesses and recursively parses/traverses an unbounded filter expression without rejecting excessive length or depth.

Attack path: Authenticate, request an accessible project's task collection with 20,000 nested parenthesis pairs around id = 1, and drive parser and expression-tree memory growth until the process is killed.

Re…

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-2026-91968 has been found in code.vikunja.io/api.
Attackers can target a specific entry point like GET /api/v2/projects/{project}/tasks over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade code.vikunja.io/api to 2.6.0 or later.
If unsure, ask your IT team or search "code.vikunja.io/api CVE-2026-91968" on the vendor's site.

CVE-2026-91968 (code.vikunja.io/api) — CWE-674 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /api/v2/projects/{project}/tasks
Patched: 2.6.0 — 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

A vulnerability (CWE-674) exists in code.vikunja.io/api. Attackers reach the vulnerable code path via GET /api/v2/projects/{project}/tasks.

📍 Affected scope

Check the vendor advisory for the affected versions of code.vikunja.io/api. Attack surface: GET /api/v2/projects/{project}/tasks.

🔥 Severity

Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 2.6.0.

🛡️ 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/v2/projects/{project}/tasks 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/v2/projects/{project}/tasks' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで GET /api/v2/projects/{project}/tasks 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 2.6.0

    ステージング環境で 2.6.0 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/v2/projects/{project}/tasks 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":"2.5.0"},{"fixed":"2.6.0"}]}]

References

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