In the Linux kernel, the following vulnerability has been resolved:
cifs: fix use-after-free bug in refresh_cache_worker()
The UAF bug occurred because we were putting DFS root sessions in cifs_umount() while DFS cache refresher was being executed.
Make DFS root sessions have same lifetime as DFS tcons so we can avoid the use-after-free bug is DFS cache refresher and other places that require IPCs to get new DFS referrals on. Also, get rid of mount group handling in DFS cache as we no longer need it.
This fixes below use-after-free bug catched by KASAN
[ 379.946955] BUG: KASAN: use-after-free in __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.947642] Read of size 8 at addr ffff888018f57030 by task kworker/u4:3/56 [ 379.948096] [ 379.948208] CPU: 0 PID: 56 Comm: kworker/u4:3 Not tainted 6.2.0-rc7-lku #23 [ 379.948661] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552-rebuilt.opensuse.org 04/01/2014 [ 379.949368] Workqueue: cifs-dfscache refresh_cache_worker [cifs] [ 379.949942] Call Trace: [ 379.950113] <TASK> [ 379.950260] dump_stack_lvl+0x50/0x67 [ 379.950510] print_report+0x16a/0x48e [ 379.950759] ? __virt_addr_valid+0xd8/0x160 [ 379.951040] ? __phys_addr+0x41/0x80 [ 379.951285] kasan_report+0xdb/0x110 [ 379.951533] ? __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.952056] ? __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.952585] __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.953096] ? __pfx___refresh_tcon.isra.0+0x10/0x10 [cifs] [ 379.953637] ? __pfx___mutex_lock+0x10/0x10 [ 379.953915] ? lock_release+0xb6/0x720 [ 379.954167] ? __pfx_lock_acquire+0x10/0x10 [ 379.954443] ? refresh_cache_worker+0x34e/0x6d0 [cifs] [ 379.954960] ? __pfx_wb_workfn+0x10/0x10 [ 379.955239] refresh_cache_worker+0x4ad/0x6d0 [cifs] [ 379.955755] ? __pfx_refresh_cache_worker+0x10/0x10 [cifs] [ 379.956323] ? __pfx_lock_acquired+0x10/0x10 [ 379.956615] ? read_word_at_a_time+0xe/0x20 [ 379.956898] ? lockdep_hardirqs_on_prepare+0x12/0x220 [ 379.957235] process_one_work+0x535/0x990 [ 379.957509] ? __pfx_process_one_work+0x10/0x10 [ 379.957812] ? lock_acquired+0xb7/0x5f0 [ 379.958069] ? __list_add_valid+0x37/0xd0 [ 379.958341] ? __list_add_valid+0x37/0xd0 [ 379.958611] worker_thread+0x8e/0x630 [ 379.958861] ? __pfx_worker_thread+0x10/0x10 [ 379.959148] kthread+0x17d/0x1b0 [ 379.959369] ? __pfx_kthread+0x10/0x10 [ 379.959630] ret_from_fork+0x2c/0x50 [ 379.959879] </TASK>
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | No solution existsUpgrade linux | May 15, 2025 | May 2, 2025 |
| Redhat_linux | — | Upgrade kernelNo solution existsUpgrade kernel-rt | Jul 9, 2025 | May 2, 2025 |
| Ubuntu | — | Upgrade linux-azureUpgrade linux-azure-5.15 | May 8, 2025 | May 2, 2025 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub