{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-90171 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-90171 is an use after free vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-90171 and fix it if it is affected.\n\nWhat it is: CVE-2026-90171 is an use after free vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-90171 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-90171/ (Markdown: https://insights.sbomify.com/CVE-2026-90171/index.md)","id":"CVE-2026-90171","markdown":"https://insights.sbomify.com/CVE-2026-90171/index.md","name":"CVE-2026-90171","record":{"aliases":["DEBIAN-CVE-2026-90171","GHSA-f5r6-6w97-7r58","UBUNTU-CVE-2026-90171"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel SMB","requires_auth":"high_privilege","summary":"A use-after-free in the Linux kernel's SMB Direct module can cause a system crash during listener shutdown, requiring high privileges to trigger.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"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\u0026id_priv-\u003ehandler_mutex taken via rdma_lock_handler(), not\nsc-\u003elisten.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]  \u003cTASK\u003e\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 (\u0026id_priv-\u003ehandler_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 (\u0026id_priv-\u003ehandler_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(\u0026id_priv-\u003ehandler_mutex);\n[ 2424.601836]   lock(\u0026id_priv-\u003ehandler_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","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"smb: smbdirect: release pending child sockets outside the handler lock","id":"CVE-2026-90171","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"smb: smbdirect: destroy QP before mem pools on accept failure","id":"CVE-2026-90172"},"packages":[],"prev":{"headline":"ksmbd: validate ipc response length before dereferencing its fields","id":"CVE-2026-90170"},"products":["Linux"],"published":"2026-09-17","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A use-after-free in the Linux kernel's SMB Direct module can cause a system crash during listener shutdown, requiring high privileges to trigger.","url":"https://insights.sbomify.com/CVE-2026-90171/"}