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CVE-2026-61740

Authentication Bypass in lightrag-hku (CVE-2026-61740)

Summary

Authentication bypass in lightrag-hku (CVE-2026-61740). Risk of unauthorized operations or information disclosure. Exploitable via DELETE /documents. Mitigation: upgrade to 1.5.4 or later.

Original description

The description as published by the source.

Summary

When LightRAG is deployed with LIGHTRAG_API_KEY set but AUTH_ACCOUNTS unset (an officially documented "API-Key authentication" mode), the X-API-Key protection can be bypassed by any remote unauthenticated attacker. The bypass does not require network contact with the victim server — an attacker can mint a valid guest JWT offline using the hardcoded DEFAULT_TOKEN_SECRET committed in the repository and then call any endpoint guarded by Depends(combined_auth), including destructive operations such as DELETE /documents, POST /documents/upload, /documents/clear_cache, and POST /query.

This is distinct from the previously-fixed GHSA-mcww-4hxq-hfr3 / CVE-2026-30762, which only covered the AUTH_ACCOUNTS-configured case. The API-Key-only deployment profile is still fully exploitable on current main (commit 157c331, v1.4.15).

Root cause

Three independent issues combine:

  1. lightrag/api/config.py:54 ships a hardcoded default JWT secret: 
    DEFAULT_TOKEN_SECRET="lightr...key!"
  2. lightrag/api/auth.py:28-38 falls back to DEFAULT_TOKEN_SECRET with only a warning log when AUTH_ACCOUNTS is not configured. The fix for CVE-2026-30762 only raises when AUTH_ACCOUNTS is set, so the API-key-only path is silently vulnerable.
  3. lightrag/api/lightrag_server.py:1140-1186 exposes GET /auth-status and POST /login without any authentication dependency. In the API-key-only configuration, auth_handler.accounts is empty, and b…

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-2026-61740 has been found in lightrag-hku.
Attackers can target a specific entry point like DELETE /documents over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade lightrag-hku to 1.5.4 or later.
If unsure, ask your IT team or search "lightrag-hku CVE-2026-61740" on the vendor's site.

CVE-2026-61740 (lightrag-hku) — CWE-287
Attack surface: DELETE /documents / POST /documents/upload / POST /query / GET /auth-status
Patched: 1.5.4 — 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

Authentication bypass (CWE-287) exists in lightrag-hku. Attackers reach the vulnerable code path via DELETE /documents.

📍 Affected scope

Check the vendor advisory for the affected versions of lightrag-hku. Attack surface: DELETE /documents / POST /documents/upload / POST /query / GET /auth-status.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.5.4.

🛡️ 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 DELETE /documents requests with malformed payloads or SQL meta-characters. Run grep -r 'lightrag-hku' . 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 'lightrag-hku' . | 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 lightrag-hku 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 'DELETE /documents' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで DELETE /documents 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 lightrag-hku to 1.5.4

    ステージング環境で 1.5.4 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 DELETE /documents 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

pip lightrag-hku
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.4"}]}]
PyPI lightrag-hku
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.4"}]}]

References

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