CVE-2026-74348
Estado: RecibidaSin puntuar—
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().
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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:
Detalles técnicos trazas, registros y código del informe original
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 (?:?)
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.22%
- Percentil entre todas las CVEs puntuadas: 11
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/03ad858ce8064861ea580021976dc19b7aabb549
- https://git.kernel.org/stable/c/5bee5d5f67aedd26d2b72e00e49dd93331fbcc30
- https://git.kernel.org/stable/c/6cc93dea4078cbcddee63fa2234e382a76600464
- https://git.kernel.org/stable/c/90a6512425414098a63fc97b77bed089c75d106b
- https://git.kernel.org/stable/c/9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a
- https://git.kernel.org/stable/c/a087b2d3411e7f9df71ba3293596923ee2c70d65
- https://git.kernel.org/stable/c/a09831214912a1f270663d935613910fafd8d883
- https://git.kernel.org/stable/c/aa7883b6a3c76301a3299deb34de948e73bb6a08
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-74348",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
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"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
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"programFiles": [
"fs/ocfs2/dlm/dlmdebug.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.26"
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{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.26",
"versionType": "semver"
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{
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
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{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/ocfs2/dlm/dlmdebug.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-15T06:22:35.970",
"references": [
{
"url": "https://git.kernel.org/stable/c/03ad858ce8064861ea580021976dc19b7aabb549",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/a087b2d3411e7f9df71ba3293596923ee2c70d65",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a09831214912a1f270663d935613910fafd8d883",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/aa7883b6a3c76301a3299deb34de948e73bb6a08",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"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->i_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->i_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->dl_ctxt and dlm_free_ctxt_mem() and frees it.\n returns success.\n4. debug_lockres_release() later\n calls dlm_put(dl->dl_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 (?:?)"
}
],
"lastModified": "2026-08-17T06:19:29.400",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}