CVE-2026-64061

/// Technical description

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

netfs: Fix early put of sink folio in netfs_read_gaps()

Fix netfs_read_gaps() to release the sink page it uses after waiting for

the request to complete. The way the sink page is used is that an

ITER_BVEC-class iterator is created that has the gaps from the target folio

at either end, but has the sink page tiled over the middle so that a single

read op can fill in both gaps.

The bug was found by KASAN detecting a UAF on the generic/075 xfstest in

the cifsd kernel thread that handles reception of data from the TCP socket:

BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20

Write of size 885 at addr ffff888107f92000 by task cifsd/1285

CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)

Call Trace:

dump_stack_lvl+0x5d/0x80

print_report+0x17f/0x4f1

kasan_report+0x100/0x1e0

kasan_check_range+0x10f/0x1e0

__asan_memcpy+0x3c/0x60

_copy_to_iter+0x48a/0xa20

__skb_datagram_iter+0x2c9/

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References