{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-92511", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-16T12:21:13.872Z", "datePublished": "2026-09-17T16:10:21.449Z", "dateUpdated": "2026-10-19T09:04:17.289Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:04:17.289Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/core: Fix potential use after free in ib_destroy_cq_user()\n\nWhen accessing a CQ via the netlink path the only synchronization\nmechanism for the said CQ is rdma_restrack_get().\nCurrently, rdma_restrack_del() is invoked at the end of\nib_destroy_cq_user(), which is too late, since by that point\nvendor-specific resources associated with the CQ might already be\nfreed. This can leave a short window where the CQ remains accessible\nthrough restrack, leading to a potential use-after-free.\n\nFix this by moving the rdma_restrack_begin_del() call to the start of\nib_destroy_cq_user(), ensuring that the CQ is removed from restrack\nbefore its internal resources are released. This guarantees that no new\nusers hold references to a CQ that is in the process of destruction.\n\nIn addition, this change preserves the intended inverted order\nbetween create and destroy routines: resources are added to\nrestrack at the end of successful creation, and hence shall be removed\nfrom the restrack first thing during the destruction flow, which keeps\nthe lifecycle management consistent and predictable." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is reached by a local IB_USER_VERBS_CMD_DESTROY_CQ/UVERBS_METHOD_CQ_DESTROY on /dev/infiniband/uverbsN (ib_uverbs_destroy_cq → uobj_get_destroy → uverbs_free_cq → ib_destroy_cq_user) racing NETLINK_RDMA RDMA_NLDEV_CMD_RES_CQ_GET (nldev_res_get_cq_doit/dumpit → rdma_restrack_get_byid/rdma_restrack_get → fill_res_cq_entry). No remote RoCE/iWARP message carries the trigger.\nAC:L - The attacker drives both sides: one thread destroys their CQ via ib_uverbs_destroy_cq/uverbs_free_cq while another issues RDMA_NLDEV_CMD_RES_CQ_GET. Pre-fix, rdma_restrack_del() ran only after cq->device->ops.destroy_cq() returned, so rdma_restrack_get() still succeeds throughout vendor teardown with no victim-controlled timing.\nPR:L - ib_uverbs_open has no CAP_* check and uverbs_devnode sets /dev/infiniband/uverbsN to 0666. RDMA_NLDEV_CMD_RES_CQ_GET is registered without RDMA_NL_ADMIN_PERM, and NETLINK_RDMA unicast to portid 0 does not require CAP_NET_ADMIN, so an unprivileged user on a system with an RDMA device can create, dump, and destroy their own CQ.\nUI:N - The attacker creates the CQ with IB_USER_VERBS_CMD_CREATE_CQ/UVERBS_METHOD_CQ_CREATE, dumps it with RDMA_NLDEV_CMD_RES_CQ_GET, and destroys it with IB_USER_VERBS_CMD_DESTROY_CQ on their own uverbs fd; no other user must mount, open a file, or otherwise act.\nS:U - fill_res_cq_entry and cq->device->ops.destroy_cq run in the same host kernel that owns the ib_cq; the dangling vendor CQ state is consumed in-kernel (nldev restrack dump versus ib_destroy_cq_user), not across a KVM/Xen, IOMMU, or other authorization boundary.\nC:H - After ib_destroy_cq_user calls destroy_cq, fill_res_cq_entry still holds the CQ via rdma_restrack_get and invokes vendor fill. c4iw_destroy_cq's destroy_cq dma_free_coherent()s cq->queue and kfree()s cq->sw_queue, then c4iw_fill_res_cq_entry copies those CQEs into the netlink skb; hns_roce_fill_res_cq_entry_raw query_cqc()s a CQN after DESTROY_CQC/hns_roce_table_put. That is a UAF read of freed CQ backing store.\nI:H - The same window leaves vendor CQ allocations (c4iw cq->queue/sw_queue, hns mtr after hns_roce_mtr_destroy, mlx5 cq->buf.umem after ib_umem_release, bnxt hwq PBLs after bnxt_qplib_free_hwq) freed while the ib_cq remains in the restrack xarray. Reclaiming those objects while fill_res_cq_entry/vendor ops still run is a UAF write/control-flow primitive.\nA:H - fill_res_cq_entry and vendor fill (c4iw_fill_res_cq_entry dereferencing dma-freed cq->queue, hns/mlx5/bnxt querying a destroyed CQN) run after destroy_cq has released those resources, so the race oopses the kernel, and repeating create_cq/destroy_cq against concurrent RDMA_NLDEV_CMD_RES_CQ_GET panics the host." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/infiniband/core/verbs.c" ], "versions": [ { "version": "08f294a1524bc3211a28091daa6c7513828c7d33", "lessThan": "42f7a0c7a94003059540cce448acabfa62ad119d", "status": "affected", "versionType": "git" }, { "version": "08f294a1524bc3211a28091daa6c7513828c7d33", "lessThan": "253c2ed71a532c70fa0e64317ceb02bb1a50c84c", "status": "affected", "versionType": "git" }, { "version": "08f294a1524bc3211a28091daa6c7513828c7d33", "lessThan": "b85a148731eceffacb6a030950187d785175607f", "status": "affected", "versionType": "git" }, { "version": "08f294a1524bc3211a28091daa6c7513828c7d33", "lessThan": "197c262dbf94c0f7ab7ac54b66f892ce9f343232", "status": "affected", "versionType": "git" }, { "version": "08f294a1524bc3211a28091daa6c7513828c7d33", "lessThan": "8a72a6aad84b3928dbb5e564bff1f56a7ec222ae", "status": "affected", "versionType": "git" }, { "version": "08f294a1524bc3211a28091daa6c7513828c7d33", "lessThan": "3481bec4dfc4aee24ffea5a547ee95b70b67d9d5", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/infiniband/core/verbs.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/42f7a0c7a94003059540cce448acabfa62ad119d" }, { "url": "https://git.kernel.org/stable/c/253c2ed71a532c70fa0e64317ceb02bb1a50c84c" }, { "url": "https://git.kernel.org/stable/c/b85a148731eceffacb6a030950187d785175607f" }, { "url": "https://git.kernel.org/stable/c/197c262dbf94c0f7ab7ac54b66f892ce9f343232" }, { "url": "https://git.kernel.org/stable/c/8a72a6aad84b3928dbb5e564bff1f56a7ec222ae" }, { "url": "https://git.kernel.org/stable/c/3481bec4dfc4aee24ffea5a547ee95b70b67d9d5" } ], "title": "RDMA/core: Fix potential use after free in ib_destroy_cq_user()", "x_generator": { "engine": "bippy-1.2.0" } } } }