CVE-2026-11856 [CRITICAL] – Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Dig

Successfully using libcurl to do a transfer to a specific HTTP origin
(`hostA`) with **Digest** authentication and then changing the origin to a
different one (`hostB`) for a second transfer, reusing the same handle, makes
libcurl wrongly pass on the `Authorization:` header field meant for `hostA`,
to `hostB`.