Executive brief
LightRAG is an open-source knowledge graph and document management system. A security flaw in its web configuration allows malicious websites to perform actions on behalf of logged-in users. If an authenticated user visits a compromised site, attackers could silently steal private documents, access knowledge graph data, or delete stored information.
Technical details
The LightRAG server defaults to a permissive Cross-Origin Resource Sharing (CORS) configuration where 'CORS_ORIGINS' is set to a wildcard ('*') while 'allow_credentials' is set to True. Due to the behavior of the underlying Starlette CORSMiddleware, when credentials are enabled with a wildcard origin, the middleware echoes the requesting origin back in the 'Access-Control-Allow-Origin' header. This effectively bypasses browser-level origin restrictions. A remote attacker can exploit this by enticing an authenticated user to visit a malicious webpage, which can then perform cross-origin authenticated API calls to the LightRAG server to exfiltrate data or delete document stores. The issue is fixed in version 1.5.4.
Affected products
- HKUDS lightrag-hku <= 1.5.3
Timeline
- 2026-06-24: disclosed: Initial report to HKUDS/LightRAG
- 2026-07-15: advisory: NVD publication date
- 2026-07-20: patched: GitHub Advisory reviewed and published; version 1.5.4 released