CVE-2025-38179

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

smb: client: fix max_sge overflow in smb_extract_folioq_to_rdma()

This fixes the following problem:

[ 749.901015] [ T8673] run fstests cifs/001 at 2025-06-17 09:40:30 [ 750.346409] [ T9870] ================================================================== [ 750.346814] [ T9870] BUG: KASAN: slab-out-of-bounds in smb_set_sge+0x2cc/0x3b0 [cifs] [ 750.347330] [ T9870] Write of size 8 at addr ffff888011082890 by task xfs_io/9870 [ 750.347705] [ T9870] [ 750.348077] [ T9870] CPU: 0 UID: 0 PID: 9870 Comm: xfs_io Kdump: loaded Not tainted 6.16.0-rc2-metze.02+ #1 PREEMPT(voluntary) [ 750.348082] [ T9870] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 750.348085] [ T9870] Call Trace: [ 750.348086] [ T9870] <TASK> [ 750.348088] [ T9870] dump_stack_lvl+0x76/0xa0 [ 750.348106] [ T9870] print_report+0xd1/0x640 [ 750.348116] [ T9870] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 750.348120] [ T9870] ? kasan_complete_mode_report_info+0x26/0x210 [ 750.348124] [ T9870] kasan_report+0xe7/0x130 [ 750.348128] [ T9870] ? smb_set_sge+0x2cc/0x3b0 [cifs] [ 750.348262] [ T9870] ? smb_set_sge+0x2cc/0x3b0 [cifs] [ 750.348377] [ T9870] __asan_report_store8_noabort+0x17/0x30 [ 750.348381] [ T9870] smb_set_sge+0x2cc/0x3b0 [cifs] [ 750.348496] [ T9870] smbd_post_send_iter+0x1990/0x3070 [cifs] [ 750.348625] [ T9870] ? __pfx_smbd_post_send_iter+0x10/0x10 [cifs] [ 750.348741] [ T9870] ? update_stack_state+0x2a0/0x670 [ 750.348749] [ T9870] ? cifs_flush+0x153/0x320 [cifs] [ 750.348870] [ T9870] ? cifs_flush+0x153/0x320 [cifs] [ 750.348990] [ T9870] ? update_stack_state+0x2a0/0x670 [ 750.348995] [ T9870] smbd_send+0x58c/0x9c0 [cifs] [ 750.349117] [ T9870] ? __pfx_smbd_send+0x10/0x10 [cifs] [ 750.349231] [ T9870] ? unwind_get_return_address+0x65/0xb0 [ 750.349235] [ T9870] ? __pfx_stack_trace_consume_entry+0x10/0x10 [ 750.349242] [ T9870] ? arch_stack_walk+0xa7/0x100 [ 750.349250] [ T9870] ? stack_trace_save+0x92/0xd0 [ 750.349254] [ T9870] __smb_send_rqst+0x931/0xec0 [cifs] [ 750.349374] [ T9870] ? kernel_text_address+0x173/0x190 [ 750.349379] [ T9870] ? kasan_save_stack+0x39/0x70 [ 750.349382] [ T9870] ? kasan_save_track+0x18/0x70 [ 750.349385] [ T9870] ? __kasan_slab_alloc+0x9d/0xa0 [ 750.349389] [ T9870] ? __pfx___smb_send_rqst+0x10/0x10 [cifs] [ 750.349508] [ T9870] ? smb2_mid_entry_alloc+0xb4/0x7e0 [cifs] [ 750.349626] [ T9870] ? cifs_call_async+0x277/0xb00 [cifs] [ 750.349746] [ T9870] ? cifs_issue_write+0x256/0x610 [cifs] [ 750.349867] [ T9870] ? netfs_do_issue_write+0xc2/0x340 [netfs] [ 750.349900] [ T9870] ? netfs_advance_write+0x45b/0x1270 [netfs] [ 750.349929] [ T9870] ? netfs_write_folio+0xd6c/0x1be0 [netfs] [ 750.349958] [ T9870] ? netfs_writepages+0x2e9/0xa80 [netfs] [ 750.349987] [ T9870] ? do_writepages+0x21f/0x590 [ 750.349993] [ T9870] ? filemap_fdatawrite_wbc+0xe1/0x140 [ 750.349997] [ T9870] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 750.350002] [ T9870] smb_send_rqst+0x22e/0x2f0 [cifs] [ 750.350131] [ T9870] ? __pfx_smb_send_rqst+0x10/0x10 [cifs] [ 750.350255] [ T9870] ? local_clock_noinstr+0xe/0xd0 [ 750.350261] [ T9870] ? kasan_save_alloc_info+0x37/0x60 [ 750.350268] [ T9870] ? __kasan_check_write+0x14/0x30 [ 750.350271] [ T9870] ? _raw_spin_lock+0x81/0xf0 [ 750.350275] [ T9870] ? __pfx__raw_spin_lock+0x10/0x10 [ 750.350278] [ T9870] ? smb2_setup_async_request+0x293/0x580 [cifs] [ 750.350398] [ T9870] cifs_call_async+0x477/0xb00 [cifs] [ 750.350518] [ T9870] ? __pfx_smb2_writev_callback+0x10/0x10 [cifs] [ 750.350636] [ T9870] ? __pfx_cifs_call_async+0x10/0x10 [cifs] [ 750.350756] [ T9870] ? __pfx__raw_spin_lock+0x10/0x10 [ 750.350760] [ T9870] ? __kasan_check_write+0x14/0x30 [ 750.350763] [ T98 ---truncated---

This vulnerability is rated as Moderate severity for Red Hat because triggering the issue requires an established SMB filesystem mount configured with the RDMA (SMB Direct) transport, an enterprise networking option not used by default. An unprivileged or local user with write access to files on such a mount could trigger a kernel slab out-of-bounds write, potentially destabilizing the operating system or escalating privileges. Deployments that do not mount remote shares using SMB Direct or that utilize standard TCP transports are not exposed to this flaw.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.