CVE-2026-74348 (GCVE-0-2026-74348)
Vulnerability from cvelistv5
Published
2026-08-15 05:58
Modified
2026-08-17 05:17
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ocfs2/dlm: require a ref for locking_state debugfs open
debug_lockres_open() copies inode->i_private into struct debug_lockres and
debug_lockres_release() later drops that pointer with dlm_put(). That
only works if open successfully pins the struct dlm_ctxt.
Today open calls dlm_grab(dlm) but ignores its return value. Once the
last domain unregister has removed the context from dlm_domains,
dlm_grab() returns NULL, yet open still stores the raw pointer and returns
success. The later release path is outside the debugfs removal barrier,
so it can call dlm_put() after dlm_free_ctxt_mem() has freed the context.
KASAN reports this as a slab-use-after-free in dlm_put() called from
debug_lockres_release().
Fail the open when dlm_grab() cannot acquire the reference and unwind the
seq_file private state before returning. That keeps locking_state from
handing out a file descriptor whose release path does not own the
dlm_ctxt.
The buggy scenario involves two paths, with each column showing the order
within that path:
locking_state debugfs open: last domain unregister:
1. debug_lockres_open() reads 1. dlm_unregister_domain() calls
inode->i_private. dlm_complete_dlm_shutdown().
2. debug_lockres_open() calls 2. shutdown removes the dlm_ctxt from
dlm_grab(dlm) and gets NULL. dlm_domains.
3. open still stores the raw dlm 3. final teardown reaches
pointer in dl->dl_ctxt and dlm_free_ctxt_mem() and frees it.
returns success.
4. debug_lockres_release() later
calls dlm_put(dl->dl_ctxt).
Validation reproduced this kernel report:
KASAN slab-use-after-free in dlm_put+0x82/0x200
RIP: 0033:0x7f4d349bc9e0
The buggy address belongs to the object at ffff888103a3c000 which belongs
to the cache kmalloc-2k of size 2048
The buggy address is located 816 bytes inside of freed 2048-byte region
[ffff888103a3c000, ffff888103a3c800)
Write of size 4
Call trace:
dump_stack_lvl+0x66/0xa0 (?:?)
print_report+0xd0/0x630 (?:?)
dlm_put+0x82/0x200 (?:?)
srso_alias_return_thunk+0x5/0xfbef5 (?:?)
__virt_addr_valid+0x188/0x2f0 (?:?)
kasan_report+0xe4/0x120 (?:?)
kasan_check_range+0x105/0x1b0 (?:?)
debug_lockres_release+0x53/0x80 (fs/ocfs2/dlm/dlmdebug.c:587)
dlm_put+0x9/0x200 (?:?)
debug_lockres_release+0x5c/0x80 (fs/ocfs2/dlm/dlmdebug.c:587)
full_proxy_release+0x67/0x90 (?:?)
__fput+0x1df/0x4b0 (?:?)
do_raw_spin_lock+0x10f/0x1b0 (?:?)
fput_close_sync+0xd2/0x170 (?:?)
__x64_sys_close+0x55/0x90 (?:?)
do_syscall_64+0x10c/0x640 (arch/x86/entry/syscall_64.c:87)
irqentry_exit+0xac/0x6e0 (?:?)
entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)
Freed by task stack:
kasan_save_stack+0x33/0x60 (?:?)
kasan_save_track+0x14/0x30 (?:?)
kasan_save_free_info+0x3b/0x60 (?:?)
__kasan_slab_free+0x5f/0x80 (?:?)
kfree+0x30f/0x580 (?:?)
dlm_put+0x1ce/0x200 (?:?)
dlm_unregister_domain+0xf6/0xb30 (?:?)
o2cb_cluster_disconnect+0x6b/0x90 (?:?)
ocfs2_cluster_disconnect+0x41/0x70 (?:?)
ocfs2_dlm_shutdown+0x1c4/0x220 (?:?)
ocfs2_dismount_volume+0x38a/0x550 (?:?)
generic_shutdown_super+0xc3/0x220 (?:?)
kill_block_super+0x29/0x60 (?:?)
deactivate_locked_super+0x66/0xe0 (?:?)
cleanup_mnt+0x13d/0x210 (?:?)
task_work_run+0xfa/0x170 (?:?)
exit_to_user_mode_loop+0xd6/0x430 (?:?)
do_syscall_64+0x3cb/0x640 (arch/x86/entry/syscall_64.c:87)
entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb Version: 4e3d24ed1a1285fe3289653aacc965642706bacb |
||
{
"containers": {
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{
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}
],
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2/dlm: require a ref for locking_state debugfs open\n\ndebug_lockres_open() copies inode-\u003ei_private into struct debug_lockres and\ndebug_lockres_release() later drops that pointer with dlm_put(). That\nonly works if open successfully pins the struct dlm_ctxt.\n\nToday open calls dlm_grab(dlm) but ignores its return value. Once the\nlast domain unregister has removed the context from dlm_domains,\ndlm_grab() returns NULL, yet open still stores the raw pointer and returns\nsuccess. The later release path is outside the debugfs removal barrier,\nso it can call dlm_put() after dlm_free_ctxt_mem() has freed the context. \nKASAN reports this as a slab-use-after-free in dlm_put() called from\ndebug_lockres_release().\n\nFail the open when dlm_grab() cannot acquire the reference and unwind the\nseq_file private state before returning. That keeps locking_state from\nhanding out a file descriptor whose release path does not own the\ndlm_ctxt.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\nlocking_state debugfs open: last domain unregister:\n1. debug_lockres_open() reads 1. dlm_unregister_domain() calls\n inode-\u003ei_private. dlm_complete_dlm_shutdown().\n2. debug_lockres_open() calls 2. shutdown removes the dlm_ctxt from\n dlm_grab(dlm) and gets NULL. dlm_domains.\n3. open still stores the raw dlm 3. final teardown reaches\n pointer in dl-\u003edl_ctxt and dlm_free_ctxt_mem() and frees it.\n returns success.\n4. debug_lockres_release() later\n calls dlm_put(dl-\u003edl_ctxt).\n\nValidation reproduced this kernel report:\nKASAN slab-use-after-free in dlm_put+0x82/0x200\nRIP: 0033:0x7f4d349bc9e0\nThe buggy address belongs to the object at ffff888103a3c000 which belongs\nto the cache kmalloc-2k of size 2048\nThe buggy address is located 816 bytes inside of freed 2048-byte region\n[ffff888103a3c000, ffff888103a3c800)\nWrite of size 4\nCall trace:\n dump_stack_lvl+0x66/0xa0 (?:?)\n print_report+0xd0/0x630 (?:?)\n dlm_put+0x82/0x200 (?:?)\n srso_alias_return_thunk+0x5/0xfbef5 (?:?)\n __virt_addr_valid+0x188/0x2f0 (?:?)\n kasan_report+0xe4/0x120 (?:?)\n kasan_check_range+0x105/0x1b0 (?:?)\n debug_lockres_release+0x53/0x80 (fs/ocfs2/dlm/dlmdebug.c:587)\n dlm_put+0x9/0x200 (?:?)\n debug_lockres_release+0x5c/0x80 (fs/ocfs2/dlm/dlmdebug.c:587)\n full_proxy_release+0x67/0x90 (?:?)\n __fput+0x1df/0x4b0 (?:?)\n do_raw_spin_lock+0x10f/0x1b0 (?:?)\n fput_close_sync+0xd2/0x170 (?:?)\n __x64_sys_close+0x55/0x90 (?:?)\n do_syscall_64+0x10c/0x640 (arch/x86/entry/syscall_64.c:87)\n irqentry_exit+0xac/0x6e0 (?:?)\n entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)\nFreed by task stack:\n kasan_save_stack+0x33/0x60 (?:?)\n kasan_save_track+0x14/0x30 (?:?)\n kasan_save_free_info+0x3b/0x60 (?:?)\n __kasan_slab_free+0x5f/0x80 (?:?)\n kfree+0x30f/0x580 (?:?)\n dlm_put+0x1ce/0x200 (?:?)\n dlm_unregister_domain+0xf6/0xb30 (?:?)\n o2cb_cluster_disconnect+0x6b/0x90 (?:?)\n ocfs2_cluster_disconnect+0x41/0x70 (?:?)\n ocfs2_dlm_shutdown+0x1c4/0x220 (?:?)\n ocfs2_dismount_volume+0x38a/0x550 (?:?)\n generic_shutdown_super+0xc3/0x220 (?:?)\n kill_block_super+0x29/0x60 (?:?)\n deactivate_locked_super+0x66/0xe0 (?:?)\n cleanup_mnt+0x13d/0x210 (?:?)\n task_work_run+0xfa/0x170 (?:?)\n exit_to_user_mode_loop+0xd6/0x430 (?:?)\n do_syscall_64+0x3cb/0x640 (arch/x86/entry/syscall_64.c:87)\n entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)"
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:17:41.148Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/6cc93dea4078cbcddee63fa2234e382a76600464"
},
{
"url": "https://git.kernel.org/stable/c/90a6512425414098a63fc97b77bed089c75d106b"
},
{
"url": "https://git.kernel.org/stable/c/5bee5d5f67aedd26d2b72e00e49dd93331fbcc30"
},
{
"url": "https://git.kernel.org/stable/c/aa7883b6a3c76301a3299deb34de948e73bb6a08"
},
{
"url": "https://git.kernel.org/stable/c/9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a"
},
{
"url": "https://git.kernel.org/stable/c/a087b2d3411e7f9df71ba3293596923ee2c70d65"
},
{
"url": "https://git.kernel.org/stable/c/a09831214912a1f270663d935613910fafd8d883"
},
{
"url": "https://git.kernel.org/stable/c/03ad858ce8064861ea580021976dc19b7aabb549"
}
],
"title": "ocfs2/dlm: require a ref for locking_state debugfs open",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74348",
"datePublished": "2026-08-15T05:58:35.977Z",
"dateReserved": "2026-08-15T05:44:03.886Z",
"dateUpdated": "2026-08-17T05:17:41.148Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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