--- id: CVE-2026-81005 title: 'ipmi: si: Fix NULL pointer dereference after failed registration' summary: |- In the Linux kernel, the following vulnerability has been resolved: ipmi: si: Fix NULL pointer dereference after failed registration try_smi_init() allocates new_smi->si_sm and later calls ipmi_register_smi_mod(), which maps to ipmi_ad… severity: medium cvss: 4.1 cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H' cvssSource: vendor cwe: - CWE-476 vendor: Linux product: Linux affected: - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 75ecc80ef0614a9f8441ab476fb748d3e919bea8 - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < b11a1e545ad7a2f8f9ba7276b4ae9429c3399456 - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < f390b0e781ca689515b659f94ef05f01497ed833 - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d377bf743f29b41729a084a633874ef9c1a13c6a - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d4be659a3e56f4eb16039ab8a1162efea086a714 - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 53af3a8bae0a93c1342e1b5519812203332aca8e - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 8ada17dd4c4ffd6b94621e735d77eda196ce118f - >- Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 6d920a75df9a83ab096b3cde7a643b656e4fdfeb - Linux 288bd736c8a027040fc261c86a87b65e7bc3f6fa - Linux >= 4.18.10 < 4.19 - Linux 4.19 published: '2026-09-11' updated: '2026-10-19' sourceUpdated: '2026-10-19T08:46:29.573Z' source: CVEORG sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-81005' references: - url: 'https://git.kernel.org/stable/c/75ecc80ef0614a9f8441ab476fb748d3e919bea8' - url: 'https://git.kernel.org/stable/c/b11a1e545ad7a2f8f9ba7276b4ae9429c3399456' - url: 'https://git.kernel.org/stable/c/f390b0e781ca689515b659f94ef05f01497ed833' - url: 'https://git.kernel.org/stable/c/d377bf743f29b41729a084a633874ef9c1a13c6a' - url: 'https://git.kernel.org/stable/c/d4be659a3e56f4eb16039ab8a1162efea086a714' - url: 'https://git.kernel.org/stable/c/53af3a8bae0a93c1342e1b5519812203332aca8e' - url: 'https://git.kernel.org/stable/c/8ada17dd4c4ffd6b94621e735d77eda196ce118f' - url: 'https://git.kernel.org/stable/c/6d920a75df9a83ab096b3cde7a643b656e4fdfeb' - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81005.json - url: 'https://access.redhat.com/security/cve/CVE-2026-81005' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532315' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-81005' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81005' - url: >- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-81005.mbox tags: - cve.org - csaf - vex - red-hat epss: 0.00177 epssPercentile: 0.07179 ingestedAt: '2026-09-14T15:23:07.454Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: ipmi: si: Fix NULL pointer dereference after failed registration try_smi_init() allocates new_smi->si_sm and later calls ipmi_register_smi_mod(), which maps to ipmi_add_smi(). During ipmi_add_smi(), the upper IPMI message handler obtains the initial BMC device information through __bmc_get_device_id(). This can fail if the BMC does not return a successful response to the Get Device ID command. When the BMC returns a nonzero completion code, the device-id helper retries the command and eventually returns -EIO if the device ID still cannot be fetched. On this failure path, ipmi_add_smi() logs "Unable to get the device id" and goes to out_err_started, where it invokes the lower driver's shutdown callback. try_smi_init() then logs the returned registration failure: ipmi_si IPI0001:00: IPMI message handler: Unable to get the device id: -5 ipmi_si IPI0001:00: Unable to register device: error -5 For ipmi_si, the shutdown callback is shutdown_smi(), which cleans up the SI state machine data, frees smi_info->si_sm, and sets smi_info->si_sm and smi_info->intf to NULL. However, intf->in_shutdown is not set on this failed-registration rollback path. Therefore, the asynchronous redo_bmc_reg work item can still retry BMC device-id probing after the lower driver has already cleared its SI state machine data. In the observed case, that retry path reached start_next_msg(), which passed the NULL smi_info->si_sm pointer to the selected KCS state machine handler: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 Workqueue: events redo_bmc_reg [ipmi_msghandler] RIP: start_kcs_transaction+0x2c/0x190 [ipmi_si] Call Trace: start_next_msg+0x50/0x80 [ipmi_si] check_start_timer_thread.part.9+0x3b/0x50 [ipmi_si] sender+0x69/0x80 [ipmi_si] i_ipmi_request+0x2ac/0x9d0 [ipmi_msghandler] __get_device_id.isra.29+0xaa/0x180 [ipmi_msghandler] __bmc_get_device_id+0xef/0x950 [ipmi_msghandler] redo_bmc_reg+0x52/0x60 [ipmi_msghandler] process_one_work+0x1a7/0x360 Set intf->in_shutdown on the out_err_started path before invoking the lower driver's shutdown callback. This prevents later redo_bmc_reg retries from using an interface whose lower driver state has been cleaned up, and applies the same shutdown state to other IPMI interfaces as well. ## Affected - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 75ecc80ef0614a9f8441ab476fb748d3e919bea8` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < b11a1e545ad7a2f8f9ba7276b4ae9429c3399456` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < f390b0e781ca689515b659f94ef05f01497ed833` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d377bf743f29b41729a084a633874ef9c1a13c6a` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d4be659a3e56f4eb16039ab8a1162efea086a714` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 53af3a8bae0a93c1342e1b5519812203332aca8e` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 8ada17dd4c4ffd6b94621e735d77eda196ce118f` - `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 6d920a75df9a83ab096b3cde7a643b656e4fdfeb` - `Linux 288bd736c8a027040fc261c86a87b65e7bc3f6fa` - `Linux >= 4.18.10 < 4.19` - `Linux 4.19` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **Red Hat VEX** · Moderate · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81005.json)