CVE-2023-53629 fs: dlm: fix use after free in midcomms commit
A use-after-free vulnerability in the Linux kernel's Distributed Lock Manager allows attackers to cause denial of service or potentially execute code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53629?
CVE-2023-53629 is a critical use after free vulnerability in Linux kernel, published on 7 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
fs: dlm: fix use after free in midcomms commit
While working on processing dlm message in softirq context I experienced the following KASAN use-after-free warning:
[ 151.760477] ================================================================== [ 151.761803] BUG: KASAN: use-after-free in dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.763414] Read of size 4 at addr ffff88811a980c60 by task lock_torture/1347
[ 151.765284] CPU: 7 PID: 1347 Comm: lock_torture Not tainted 6.1.0-rc4+ #2828 [ 151.766778] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.16.0-3.module+el8.7.0+16134+e5908aa2 04/01/2014 [ 151.768726] Call Trace: [ 151.769277] <TASK> [ 151.769748] dump_stack_lvl+0x5b/0x86 [ 151.770556] print_report+0x180/0x4c8 [ 151.771378] ? kasan_complete_mode_report_info+0x7c/0x1e0 [ 151.772241] ? dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.773069] kasan_report+0x93/0x1a0 [ 151.773668] ? dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.774514] __asan_load4+0x7e/0xa0 [ 151.775089] dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.775890] ? create_message.isra.29.constprop.64+0x57/0xc0 [ 151.776770] send_common+0x19f/0x1b0 [ 151.777342] ? remove_from_waiters+0x60/0x60 [ 151.778017] ? lock_downgrade+0x410/0x410 [ 151.778648] ? __this_cpu_preempt_check+0x13/0x20 [ 151.779421] ? rcu_lockdep_current_cpu_online+0x88/0xc0 [ 151.780292] _convert_lock+0x46/0x150 [ 151.780893] convert_lock+0x7b/0xc0 [ 151.781459] dlm_lock+0x3ac/0x580 [ 151.781993] ? 0xffffffffc0540000 [ 151.782522] ? torture_stop+0x120/0x120 [dlm_locktorture] [ 151.783379] ? dlm_scan_rsbs+0xa70/0xa70 [ 151.784003] ? preempt_count_sub+0xd6/0x130 [ 151.784661] ? is_module_address+0x47/0x70 [ 151.785309] ? torture_stop+0x120/0x120 [dlm_locktorture] [ 151.786166] ? 0xffffffffc0540000 [ 151.786693] ? lockdep_init_map_type+0xc3/0x360 [ 151.787414] ? 0xffffffffc0540000 [ 151.787947] torture_dlm_lock_sync.isra.3+0xe9/0x150 [dlm_locktorture] [ 151.789004] ? torture_stop+0x120/0x120 [dlm_locktorture] [ 151.789858] ? 0xffffffffc0540000 [ 151.790392] ? lock_torture_cleanup+0x20/0x20 [dlm_locktorture] [ 151.791347] ? delay_tsc+0x94/0xc0 [ 151.791898] torture_ex_iter+0xc3/0xea [dlm_locktorture] [ 151.792735] ? torture_start+0x30/0x30 [dlm_locktorture] [ 151.793606] lock_torture+0x177/0x270 [dlm_locktorture] [ 151.794448] ? torture_dlm_lock_sync.isra.3+0x150/0x150 [dlm_locktorture] [ 151.795539] ? lock_torture_stats+0x80/0x80 [dlm_locktorture] [ 151.796476] ? do_raw_spin_lock+0x11e/0x1e0 [ 151.797152] ? mark_held_locks+0x34/0xb0 [ 151.797784] ? _raw_spin_unlock_irqrestore+0x30/0x70 [ 151.798581] ? __kthread_parkme+0x79/0x110 [ 151.799246] ? trace_preempt_on+0x2a/0xf0 [ 151.799902] ? __kthread_parkme+0x79/0x110 [ 151.800579] ? preempt_count_sub+0xd6/0x130 [ 151.801271] ? __kasan_check_read+0x11/0x20 [ 151.801963] ? __kthread_parkme+0xec/0x110 [ 151.802630] ? lock_torture_stats+0x80/0x80 [dlm_locktorture] [ 151.803569] kthread+0x192/0x1d0 [ 151.804104] ? kthread_complete_and_exit+0x30/0x30 [ 151.804881] ret_from_fork+0x1f/0x30 [ 151.805480] </TASK>
[ 151.806111] Allocated by task 1347: [ 151.806681] kasan_save_stack+0x26/0x50 [ 151.807308] kasan_set_track+0x25/0x30 [ 151.807920] kasan_save_alloc_info+0x1e/0x30 [ 151.808609] __kasan_slab_alloc+0x63/0x80 [ 151.809263] kmem_cache_alloc+0x1ad/0x830 [ 151.809916] dlm_allocate_mhandle+0x17/0x20 [ 151.810590] dlm_midcomms_get_mhandle+0x96/0x260 [ 151.811344] _create_message+0x95/0x180 [ 151.811994] create_message.isra.29.constprop.64+0x57/0xc0 [ 151.812880] send_common+0x129/0x1b0 [ 151.813467] _convert_lock+0x46/0x150 [ 151.814074] convert_lock+0x7b/0xc0 [ 151.814648] dlm_lock+0x3ac/0x580 [ 151.815199] torture_dlm_lock_sync.isra.3+0xe9/0x150 [dlm_locktorture] [ 151.816258] torture_ex_iter+0xc3/0xea [dlm_locktorture] [ 151.817129] lock_t ---truncated---
Weakness: CWE-416
Which versions are affected by CVE-2023-53629?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53629?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-53629 being exploited?
There is no known exploitation of CVE-2023-53629 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-76407, BELL-CVE-2023-53629, DEBIAN-CVE-2023-53629, GHSA-rf27-4m25-62jv, ROOT-OS-UBUNTU-2204-CVE-2023-53629, UBUNTU-CVE-2023-53629.