LightRAG servers, before version 1.5.4, set the CORS_ORIGINS value to a wildcard and enabled allow_credentials=True. This configuration instructs Starlette's CORSMiddleware to accept authenticated cross‑origin requests from any origin. Consequently, a malicious website visited by an authenticated LightRAG user can silently issue API calls that carry the user’s credentials, allowing the attacker to read documents, download knowledge‑graph data, or perform destructive actions such as deleting the document store. The vulnerability is an example of improper access control in a cross‑origin context, mapped to CWE‑942.

The affected product is LightRAG from HKUDS. All releases prior to 1.5.4 are vulnerable; the issue was addressed in the 1.5.4 release. No specific downstream product or platform is listed, so any deployment of the vulnerable LightRAG version is susceptible.

The CVSS score of 9.3 indicates a high‑impact vulnerability. Although the EPSS score is below 1 %, indicating a relatively low probability of exploitation at the time of analysis, the risk remains significant because the attack vector—any website the user visits—can be easily controlled by attackers. The vulnerability is not listed in CISA’s KEV catalog. An attacker would need a user who is authenticated to the LightRAG instance; once that condition is met, the attacker can make credentialed requests purely through normal browser navigation to a malicious origin.