CVE-2026-89507
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: RDMA/ucma: Lock the handler in ucma_write_cm_event() ctx->file may only be changed under the handler lock and the xa_lock, which is what stops uevents being queued for a ctx while ucma_migrate_id() moves it to another file. The CM core takes that lock before invoking ucma_event_handler(), but the write() paths that queue uevents themselves do not. ucma_write_cm_event() re-reads ctx->file for each of its four dereferences, so ucma_migrate_id() can swap it mid-sequence: mutex_lock(&ctx->file->mut); /* file A */ list_add_tail(&uevent->list, &ctx->file->event_list); /* file B */ mutex_unlock(&ctx->file->mut); /* file B */ wake_up_interruptible(&ctx->file->poll_wait); /* file B */ The window is the mutex_lock() itself: the writer sleeps in it while the migration reassigns ctx->file. The list_add_tail() then runs on file B's event_list holding only file A's mutex: list_add corruption. prev->next should be next (ffff888101320f30), but was ffff88814a08c418. (prev=ffff88814a075c18). kernel BUG at lib/list_debug.c:32! Call Trace: ucma_write_cm_event+0x36e/0x5e0 and file A's mut is left held forever, wedging its next writer in D state. The uevent is also stranded on a list ucma_cleanup_ctx_events() will not walk, so it outlives its context. /dev/infiniband/rdma_cm is 0666 and no RDMA device is involved, so an unprivileged user reaches all of this. Take the handler lock, as ucma_cleanup_mc_events() does; ctx->cm_id is pinned by the ucma_get_ctx() reference.
View original CVE JSON
{
"id": "CVE-2026-89507",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-11T20:19:33.027",
"lastModified": "2026-10-19T09:17:44.940",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/ucma: Lock the handler in ucma_write_cm_event()\n\nctx->file may only be changed under the handler lock and the xa_lock, which\nis what stops uevents being queued for a ctx while ucma_migrate_id() moves\nit to another file. The CM core takes that lock before invoking\nucma_event_handler(), but the write() paths that queue uevents themselves\ndo not.\n\nucma_write_cm_event() re-reads ctx->file for each of its four dereferences,\nso ucma_migrate_id() can swap it mid-sequence:\n\n\tmutex_lock(&ctx->file->mut);\t\t\t/* file A */\n\tlist_add_tail(&uevent->list, &ctx->file->event_list);\t/* file B */\n\tmutex_unlock(&ctx->file->mut);\t\t\t/* file B */\n\twake_up_interruptible(&ctx->file->poll_wait);\t/* file B */\n\nThe window is the mutex_lock() itself: the writer sleeps in it while the\nmigration reassigns ctx->file. The list_add_tail() then runs on file B's\nevent_list holding only file A's mutex:\n\n list_add corruption. prev->next should be next (ffff888101320f30),\n but was ffff88814a08c418. (prev=ffff88814a075c18).\n kernel BUG at lib/list_debug.c:32!\n Call Trace:\n ucma_write_cm_event+0x36e/0x5e0\n\nand file A's mut is left held forever, wedging its next writer in D state.\nThe uevent is also stranded on a list ucma_cleanup_ctx_events() will not\nwalk, so it outlives its context. /dev/infiniband/rdma_cm is 0666 and no\nRDMA device is involved, so an unprivileged user reaches all of this.\n\nTake the handler lock, as ucma_cleanup_mc_events() does; ctx->cm_id is\npinned by the ucma_get_ctx() reference."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/infiniband/core/ucma.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5",
"lessThan": "4f8bb11dd2ff365e7cff1c9964ab4607292d364e",
"versionType": "git",
"status": "affected"
},
{
"version": "a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5",
"lessThan": "0be1955040a2eceed0ecfc387fdc92305411d273",
"versionType": "git",
"status": "affected"
},
{
"version": "a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5",
"lessThan": "f4cc21c6a8e9d392871477f9fd98d68e5ad80272",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"drivers/infiniband/core/ucma.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.18",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.18",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.50",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.4",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/0be1955040a2eceed0ecfc387fdc92305411d273",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/4f8bb11dd2ff365e7cff1c9964ab4607292d364e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f4cc21c6a8e9d392871477f9fd98d68e5ad80272",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}