A flaw in curl causes the client to forward Kerberos authentication details when following HTTP redirects. The vulnerability leads to the exposure of sensitive authentication credentials and is classified as an information exposure weakness. As a result, an attacker could potentially learn a user's Kerberos credentials without the user's knowledge.

Curl clients executing Negotiate (Kerberos) authentication and configured to follow redirects are affected. No specific product version is listed, so any version of curl that supports Kerberos authentication and automatic redirection could be vulnerable.

The CVSS score of 5.3 indicates moderate severity, and the EPSS score is not available, so the exploitation probability is uncertain. The vulnerability is not listed in CISA KEV, suggesting no widely known exploits have been documented yet. An attacker can exploit the flaw by acting as a malicious server that issues a redirect containing embedded user credentials; when the curl client follows the redirect, it inadvertently sends those credentials to an unrelated destination. The attack vector is inferred to be a remote server that controls the redirect target, leveraging the client’s trust in HTTP redirects.