CVE-2026-86415

A flaw was found in curl. In builds configured with the Microsoft Schannel Transport Layer Security (TLS) backend, libcurl's connection cache fails to evaluate client certificate authentication settings when handling HTTP redirects. A malicious server can redirect a transfer to a different destination, causing curl to inappropriately reuse an already authenticated connection. This issue can result in information disclosure by exposing client certificates and credentials to unintended origins.

This vulnerability is rated as Low impact for Red Hat products because exploitation is restricted to builds utilizing the Windows-specific Schannel TLS backend. Red Hat distributions compile curl and libcurl with OpenSSL rather than Schannel. As a result, the vulnerable code paths are not present or active in Red Hat environments.

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.