CVE-2026-64061

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> netfs: Fix early put of sink folio in netfs_read_gaps()<br /> <br /> Fix netfs_read_gaps() to release the sink page it uses after waiting for<br /> the request to complete. The way the sink page is used is that an<br /> ITER_BVEC-class iterator is created that has the gaps from the target folio<br /> at either end, but has the sink page tiled over the middle so that a single<br /> read op can fill in both gaps.<br /> <br /> The bug was found by KASAN detecting a UAF on the generic/075 xfstest in<br /> the cifsd kernel thread that handles reception of data from the TCP socket:<br /> <br /> BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20<br /> Write of size 885 at addr ffff888107f92000 by task cifsd/1285<br /> CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)<br /> Call Trace:<br /> dump_stack_lvl+0x5d/0x80<br /> print_report+0x17f/0x4f1<br /> kasan_report+0x100/0x1e0<br /> kasan_check_range+0x10f/0x1e0<br /> __asan_memcpy+0x3c/0x60<br /> _copy_to_iter+0x48a/0xa20<br /> __skb_datagram_iter+0x2c9/0x430<br /> skb_copy_datagram_iter+0x6e/0x160<br /> tcp_recvmsg_locked+0xce0/0x1130<br /> tcp_recvmsg+0xeb/0x300<br /> inet_recvmsg+0xcf/0x3a0<br /> sock_recvmsg+0xea/0x100<br /> cifs_readv_from_socket+0x3a6/0x4d0 [cifs]<br /> cifs_read_iter_from_socket+0xdd/0x130 [cifs]<br /> cifs_readv_receive+0xaad/0xb10 [cifs]<br /> cifs_demultiplex_thread+0x1148/0x1740 [cifs]<br /> kthread+0x1cf/0x210