Curl, a widely used command‑line tool and library, contains a flaw that allows ambient user credentials—where authentication occurs implicitly— to lead to improper reuse of an existing Negotiate‑authenticated connection for a different server origin. As a result, requests intended for one server can be transmitted over a connection that is authenticated to another, potentially exposing data on the target server. The weakness is identified as CWE‑201, reflecting unauthorized information disclosure through improper handling of credentials.

The vulnerability affects the curl application and its libraries; no specific version range is provided, indicating that all releases prior to a later patch may be impacted. Any system that uses curl for HTTP(S) requests under environments where Negotiate authentication is enabled and where ambient credentials are in use is at risk.

The CVSS score of 3.7 indicates a low‑to‑medium severity. EPSS data is not available, and the vulnerability is not listed in the CISA KEV catalog, which suggests that widespread exploitation is unlikely at present. Attackers would need to convince a user running curl to perform a request that uses ambient credentials, after which the connection could be abused to send data to an unintended third‑party server. The lack of an exploit score and KEV listing further mitigates immediate concern, but the risk of accidental information disclosure remains. Vigilance and mitigation are advised.