CVE-2025-38139

/// Technical description

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

netfs: Fix oops in write-retry from mis-resetting the subreq iterator

Fix the resetting of the subrequest iterator in netfs_retry_write_stream()

to use the iterator-reset function as the iterator may have been shortened

by a previous retry. In such a case, the amount of data to be written by

the subrequest is not "subreq->len" but "subreq->len -

subreq->transferred".

Without this, KASAN may see an error in iov_iter_revert():

BUG: KASAN: slab-out-of-bounds in iov_iter_revert lib/iov_iter.c:633 [inline]

BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611

Read of size 4 at addr ffff88802912a0b8 by task kworker/u32:7/1147

CPU: 1 UID: 0 PID: 1147 Comm: kworker/u32:7 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full)

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014

Workqueue: events_unbound netfs_write_co

/// 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