DocsGPT versions up to 0.20.0 allow the application to post OAuth connector session tokens to a wildcard target origin in the callback‑status endpoint without validating the sender origin. An attacker can act as window.opener during OAuth authorization, intercept the token and the provider account email, and then use the token to disconnect the victim’s cloud storage connectors. This flaw is a CWE‑346 information‑exposure vulnerability and results in credential compromise and potential service disruption.

All installations of arc53:DocsGPT through version 0.20.0 are affected. No other versions or editions are known to be impacted. The issue originates from the generic postMessage implementation used during the OAuth callback.

The CVSS score of 5.3 indicates medium severity, and the EPSS score is reported as < 1%. The vulnerability is not listed in CISA KEV. The likely attack requires the attacker to coerce the victim into opening an OAuth flow from a malicious context, becoming the window.opener of the DocsGPT authorization window. The attacker then captures the postMessage payload to obtain the session token and provider email, after which the token can be used to request a disconnection of the victim’s cloud connector, disabling file access and user data synchronization. Because the attacker must trick the user into visiting a malicious URL, the exploitation probability is low as indicated by the EPSS score.