AFAICS, this was exposed by the addition of sockfs_setattr() in v4.10. So it's incorrect to claim that kernels older than that are vulnerable, even though the code being fixed was older.<p>Also, note that there may not actually be a proof-of-concept exploit yet, beyond a reproducer causing a KASAN splat. When people request a CVE for a use-after-free bug they usually just assume that code execution may be possible. (Exploits can be very creative.)
Looks like this is the fix:<p><a href="https://github.com/torvalds/linux/commit/9060cb719e61b685ec0102574e10337fa5f445ea" rel="nofollow">https://github.com/torvalds/linux/commit/9060cb719e61b685ec0...</a>
FYI there has not ever been a Linux kernel that lacks an exploit available to, at least, local users. There is every reason to believe that the current kernel contains at least one such flaw.
I really shouldn't comment on Linux kernel development, given mu lack of knowledge, but since this is a use-after-free vuln, doesn't that strengthen the case to moving to memory safe languages?