{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98360", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.344Z", "datePublished": "2026-10-06T08:46:46.743Z", "dateUpdated": "2026-10-19T09:18:11.284Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:18:11.284Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: insert mcg into mcg_tree only after rxe_mcast_add() succeeds\n\nrxe_get_mcg() publishes a newly allocated multicast group in\nrxe->mcg_tree before programming the backing Ethernet multicast address\nwith rxe_mcast_add(), which runs outside mcg_lock. A local userspace\nRDMA client reaches this path with ATTACH_MCAST on a UD QP; if\nrxe_mcast_add() then returns an error (for example -ENODEV when the\nbacking netdev has been removed, or a propagated dev_mc_add() error),\nthe unwind frees the published group without removing it from the tree.\nA later lookup of the same MGID dereferences the freed struct rxe_mcg\nfrom __rxe_lookup_mcg().\n\nFix this by keeping the new mcg private until rxe_mcast_add() succeeds.\nSplit the tree publication into __rxe_publish_mcg(), call rxe_mcast_add()\nbefore taking the tree reference, and free the still-private mcg on\nfailure. Because the group is never visible in mcg_tree until the\nmulticast address is programmed, no concurrent caller can look it up or\nattach a QP to a group that is about to be torn down, so the error path\nneeds no conditional unwind. If another caller publishes the same MGID\nwhile the address is being programmed, the post-add re-check under\nmcg_lock finds the winner; this caller then drops its private object and\nbalances its own rxe_mcast_add() with rxe_mcast_del() before returning\nthe winner.\n\nReproduced by forcing the rxe_mcast_add() error return under KASAN:\nwithout the change the next attach to the same MGID reports a\nslab-use-after-free in __rxe_lookup_mcg(); with it the forced failure\nreturns cleanly. A no-injection attach/detach regression, including a\ntwo-QP shared join/leave and re-attach, stays KASAN- and leak-clean." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The faulty publish-then-free sequence is in rxe_get_mcg(), reached from the uverbs ATTACH_MCAST command (ib_uverbs_attach_mcast -> ib_attach_mcast -> rxe_attach_mcast) on a local UD QP. A remote RoCEv2 multicast packet (rxe_rcv_mcast_pkt -> rxe_lookup_mcg) can only hit the stale node after a local caller has already caused the failure.\nAC:H - The dangling mcg is only left behind when rxe_mcast_add() fails after the group is published. That needs ib_device_get_netdev() to return NULL while the rxe netdev is being unregistered (an admin or hardware event), or a GFP_ATOMIC failure in __hw_addr_create(). An unprivileged user cannot produce either on demand.\nPR:L - ib_uverbs_attach_mcast() and rxe_attach_mcast() have no capability check, so any user who can open the rxe uverbs device and create a UD QP can drive rxe_get_mcg(). Creating the rxe link itself (RDMA_NL_ADMIN_PERM, checked with netlink_capable against the init namespace) is admin setup the attacker does not perform.\nUI:N - The attacker issues ATTACH_MCAST for the failing MGID and then the follow-up attach/detach/lookup themselves; no other user has to act.\nS:U - The freed rxe_mcg is kernel heap memory in the same kernel security authority; there is no VM, IOMMU or sandbox boundary crossed.\nC:H - The freed struct rxe_mcg stays linked in rxe->mcg_tree. __rxe_lookup_mcg() walks its rb_node and mgid, and later code follows its qp_list, so reallocating that slab slot with attacker-chosen data gives a heap read primitive.\nI:H - After the free, __rxe_lookup_mcg() does kref_get() on the stale object, and rxe_attach_mcg() list_add()s an mca into its qp_list and updates qp_num. These are writes into reallocated memory, and the rb-tree insert/erase relinks through the freed node.\nA:H - The next ATTACH_MCAST, detach, or received multicast lookup for that MGID dereferences the freed rxe_mcg (KASAN slab-use-after-free in __rxe_lookup_mcg()), corrupting the rb-tree and crashing the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/infiniband/sw/rxe/rxe_mcast.c" ], "versions": [ { "version": "a926a903b7dc39a8a949150258c09290998dd812", "lessThan": "ddb43ac0926d4a931bc9b7744b93627f627457e5", "status": "affected", "versionType": "git" }, { "version": "a926a903b7dc39a8a949150258c09290998dd812", "lessThan": "c79a789aa15180a1543b5db49c343d12e3ec214d", "status": "affected", "versionType": "git" }, { "version": "a926a903b7dc39a8a949150258c09290998dd812", "lessThan": "faae1fb4ccf8205806a8802c008798dabeb0205b", "status": "affected", "versionType": "git" }, { "version": "a926a903b7dc39a8a949150258c09290998dd812", "lessThan": "02c0a2fa69c16248a7432af8a6d64ab2a73a5283", "status": "affected", "versionType": "git" }, { "version": "a926a903b7dc39a8a949150258c09290998dd812", "lessThan": "d4fc4e37f8a143b0fe83b42c8fb48cf542154fee", "status": "affected", "versionType": "git" }, { "version": "a926a903b7dc39a8a949150258c09290998dd812", "lessThan": "1caceeb2d74bbe88223aea55eb8626b4c5f076fd", "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/sw/rxe/rxe_mcast.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "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": "5.18", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.18.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ddb43ac0926d4a931bc9b7744b93627f627457e5" }, { "url": "https://git.kernel.org/stable/c/c79a789aa15180a1543b5db49c343d12e3ec214d" }, { "url": "https://git.kernel.org/stable/c/faae1fb4ccf8205806a8802c008798dabeb0205b" }, { "url": "https://git.kernel.org/stable/c/02c0a2fa69c16248a7432af8a6d64ab2a73a5283" }, { "url": "https://git.kernel.org/stable/c/d4fc4e37f8a143b0fe83b42c8fb48cf542154fee" }, { "url": "https://git.kernel.org/stable/c/1caceeb2d74bbe88223aea55eb8626b4c5f076fd" } ], "title": "RDMA/rxe: insert mcg into mcg_tree only after rxe_mcast_add() succeeds", "x_generator": { "engine": "bippy-1.2.0" } } } }