CVE-2026-97610

In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix uninitialized return value in netfs unbuffered write()

If preparation of the first subrequest fails, netfs unbuffered write() exits its loop before ret is initialized. The empty-iterator check can do the same.

For synchronous writes, netfs unbuffered write iter locked() may then return an unrelated error instead of wreq->error. This is reachable through CIFS if cifs prepare write() fails to reopen the file or obtain credits.

Initialize ret to 0 so the caller returns wreq->error if no data was written, or the number of bytes already written otherwise.

Found with Clang's -Wconditional-uninitialized.