{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-90171", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-90171", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-09-17T16:06:59.150Z", "updatedAt": "2026-10-19T08:59:08.551Z", "importedAt": "2026-10-24T01:58:35.090Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "smb: smbdirect: release pending child sockets outside the handler lock", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: smbdirect: release pending child sockets outside the handler lock\n\nsmbdirect_socket_destroy() releases the listener's pending/ready child\nsockets while still holding the listener's handler lock, the\n&id_priv->handler_mutex taken via rdma_lock_handler(), not\nsc->listen.lock, and before the listener's own rdma_destroy_id().\nThat ordering has one real consequence and one cosmetic one.\n\nThe real one: smbdirect_socket_release() drops the child's last\nreference, which destroys the child's cm_id. Doing that before the\nlistener's rdma_destroy_id() lets _cma_cancel_listens(), running from\nthe listener's _destroy_id(), walk an already freed child id_priv,\nwhich KASAN catches as a slab-use-after-free during listener shutdown:\n\n[ 4758.909130] BUG: KASAN: slab-use-after-free in __mutex_lock+0x1469/0x1560\n[ 4758.911450] Read of size 1 at addr ffff88821c381db4 by task ksmbd.control/1652\n[ 4758.913262] Call Trace:\n[ 4758.913267] \n[ 4758.913299] __mutex_lock+0x1469/0x1560\n[ 4758.913408] _cma_cancel_listens+0x312/0x3b0\n[ 4758.913413] _destroy_id+0x363/0xee0\n[ 4758.913417] smbdirect_socket_destroy_sync+0x17d5/0x2440\n[ 4758.913443] smbdirect_socket_release+0x124/0x230\n[ 4758.913451] ksmbd_rdma_stop_listening+0x9f/0x190\n[ 4758.913457] ksmbd_conn_transport_destroy+0x65/0x3c0\n[ 4758.913463] kill_server_store+0x1fb/0x2b0\n[ 4758.913501] kernfs_fop_write_iter+0x349/0x4d0\n[ 4758.913507] vfs_write+0x5e7/0xc70\n[ 4758.913528] ksys_write+0x12a/0x210\n[ 4758.913541] do_syscall_64+0x135/0x460\n[ 4758.913555] entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nThe cosmetic one: releasing a child recurses into\nsmbdirect_socket_destroy(), which takes the child's own\nrdma_lock_handler() lock nested under the listener's. The listener's\nand the child's cm_id are always different instances, so this cannot\ndeadlock for real; the CM core itself nests a new connection id's\nhandler_mutex under the listening id's in cma_ib_req_handler(). But\nlockdep only sees one lock class, reports possible recursive locking,\nand then disables itself, hiding real locking bugs for the rest of the\nrun:\n\n[ 2424.579653] WARNING: possible recursive locking detected\n[ 2424.581180] 7.1.0-next-20260623+ #89 Not tainted\n[ 2424.582548] --------------------------------------------\n[ 2424.584500] ksmbd.control/8854 is trying to acquire lock:\n[ 2424.586817] ffff888102303c20 (&id_priv->handler_mutex){+.+.}-{4:4}, at: smbdirect_socket_destroy_sync+0xc39/0x2440\n[ 2424.590590]\n[ 2424.590590] but task is already holding lock:\n[ 2424.591601] ffff888102046c20 (&id_priv->handler_mutex){+.+.}-{4:4}, at: smbdirect_socket_destroy_sync+0xc39/0x2440\n[ 2424.594178]\n[ 2424.594178] other info that might help us debug this:\n[ 2424.596634] Possible unsafe locking scenario:\n[ 2424.596634]\n[ 2424.598841] CPU0\n[ 2424.599765] ----\n[ 2424.600695] lock(&id_priv->handler_mutex);\n[ 2424.601836] lock(&id_priv->handler_mutex);\n[ 2424.602590]\n[ 2424.602590] *** DEADLOCK ***\n[ 2424.602590]\n[ 2424.604512] May be due to missing lock nesting notation\n\nSplice the pending/ready children onto a local list under the\nlistener's listen.lock, while the handler lock is held so a concurrent\nCM CONNECT_REQUEST cannot add more, but defer the actual\nsmbdirect_socket_release() calls until after the listener's cm_id has\nbeen destroyed and its handler lock dropped. The children are\nindependent sockets whose teardown needs neither the listener's\nhandler lock nor its cm_id.\n\nFound with ksmbdzzer [2], a KSMBD fuzzer that drives libFuzzer with a\nkcov-dataflow [1] coverage vector: it folds each instrumented\ncomparison/argument's runtime operand value together with its PC (the\ndefault arm mixes them as pc⊕val) so that a new operand value at a known\nsite counts as new coverage.\n\n[1] https://lwn.net/Articles/1077606/\n[2] https://github.com/yskzalloc/kcov-dataflow", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "dc691b91ad1677def14582a279e56fd943b52f94", "status": "affected", "versionType": "git", "lessThan": "8ea83ef0c40ec4463695e22bc9ae43e29bcfede7" }, { "version": "dc691b91ad1677def14582a279e56fd943b52f94", "status": "affected", "versionType": "git", "lessThan": "db82fbe4bb68e68e4aef00ef5b79f92991d8ef8e" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "7.1", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "7.1" }, { "version": "7.2.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }