CVE-2026-86413

A flaw was found in curl. When curl is configured to follow HTTP redirects while performing Negotiate authentication using system-provided Kerberos credentials, it may forward authentication details to an unrelated destination. A malicious server can exploit this flaw by redirecting the client to a target URL containing embedded user credentials, resulting in information disclosure of sensitive authentication data.

Red Hat rates this vulnerability as Low impact because successful credential exposure requires an uncommon combination of conditions: an HTTP request using Negotiate authentication with ambient Kerberos credentials must be configured to follow redirects to a secondary URL with embedded credentials. Furthermore, core Red Hat Enterprise Linux distributions ship curl versions outside the affected upstream release window. In typical enterprise environments, Kerberos-authenticated transfers rarely follow automated redirects across disparate origins, significantly limiting exposure in practice.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.