{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89486", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.712Z", "datePublished": "2026-09-11T19:43:40.116Z", "dateUpdated": "2026-10-19T08:47:36.844Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:47:36.844Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()\n\nCommit 9e91f8a6c868 (\"ipmi:msghandler: Remove srcu for the\nipmi_interfaces list\") dropped the synchronize_rcu() between unlinking\nthe command receivers from intf->cmd_rcvrs and freeing them, updating\nonly the comment that explains why the barrier is needed.\n\nThe cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr()\nwalks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows\nrcvr->user from that lookup within the same read-side section. Without\nthe grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a\nreader still holds a pointer to it, causing a use-after-free.\n\nThe rework only made srcu unnecessary for the interfaces list; the\ncmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu()\nbefore freeing the receivers." } ], "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 close/release on /dev/ipmiN (ipmi_release → ipmi_destroy_user → _ipmi_destroy_user) after IPMICTL_REGISTER_FOR_CMD; BMC GET_MSG/IPMB/LAN command delivery is the RCU reader, not Linux network-packet processing, so the attack remains local like other /dev/ipmiN IPMI bugs.\nAC:L - The attacker controls the free side (open, register-for-cmd, close) and arms command watching, then races close against GET_MSG/IPMB/LAN command handling they can induce via their own IPMI ioctls and typical host-to-BMC access; this is an attacker-driven UAF race, not a layout or victim-state condition.\nPR:L - ipmi_open, ipmi_create_user, and IPMICTL_REGISTER_FOR_CMD perform no capable() check; access is only DAC on /dev/ipmiN, which server and appliance deployments routinely grant to a non-root ipmi/management group for ipmitool/freeipmi, matching established IPMI scoring.\nUI:N - The attacker opens, registers, and closes their own /dev/ipmiN file descriptors and issues ioctls themselves; no victim action such as mounting a filesystem or opening a hostile file is required.\nS:U - This is a host-kernel heap use-after-free of struct cmd_rcvr in the IPMI message handler; impact stays in the same OS security authority with no VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Without synchronize_rcu(), find_cmd_rcvr() and handle_*_get_msg_cmd() read rcvr->user from a kmalloc'd cmd_rcvr that _ipmi_destroy_user() already kfree()d; reclaiming that object yields an attacker-controlled pointer and a kernel read primitive, so confidentiality is High per UAF guidance.\nI:H - A sprayed cmd_rcvr supplies a fake ipmi_user pointer; ipmi_alloc_recv_msg() then updates nr_msgs/refcount through that pointer and smi_work later invokes user->handler->ipmi_recv_hndl, enabling heap spray and control-flow hijack for arbitrary write and code execution.\nA:H - Use-after-free of cmd_rcvr during the RCU list walk and the subsequent dangling user-pointer dereference readily oopses or panics the kernel under poisoning/KASAN, so availability impact is High per UAF guidance." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/char/ipmi/ipmi_msghandler.c" ], "versions": [ { "version": "9e91f8a6c8688e27f4ccce7db457da87d6458836", "lessThan": "3088e41292fecf132f85f79af5ee4d620b9ff1b4", "status": "affected", "versionType": "git" }, { "version": "9e91f8a6c8688e27f4ccce7db457da87d6458836", "lessThan": "5dc0b2a9af95a97861c1bffaf1687a3173e395c5", "status": "affected", "versionType": "git" }, { "version": "9e91f8a6c8688e27f4ccce7db457da87d6458836", "lessThan": "05ec76cfbce653e07cec19b9b8b20e33449d5d87", "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/char/ipmi/ipmi_msghandler.c" ], "versions": [ { "version": "6.16", "status": "affected" }, { "version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "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": "6.16", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4" }, { "url": "https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5" }, { "url": "https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87" } ], "title": "ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()", "x_generator": { "engine": "bippy-1.2.0" } } } }