CVE-2026-64414

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

netfilter: handle unreadable frags

sashiko reports:

When an skb with unreadable fragments (such as from devmem TCP, where

skb_frags_readable(skb) returns false) is processed by the u32 module,

skb_copy_bits() will safely return a negative error code [..]

xt_u32: bail out with hotdrop in this case.

gather_frags: return -1, just as if we had no fragment header.

nfnetlink_queue: restrict to the linear part.

nfnetlink_log: restrict to the linear part.

v2:

- skb_zerocopy helpers don't copy readable flag, i.e. nfnetlink_queue

is broken too

xt_u32 shouldn't return true if hotdrop was set.