GHSA-36X4-6H38-8GRW
Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32In 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": [],
"aliases": [
"CVE-2026-81005"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-11T20:19:09Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: si: Fix NULL pointer dereference after failed registration\n\ntry_smi_init() allocates new_smi-\u003esi_sm and later calls\nipmi_register_smi_mod(), which maps to ipmi_add_smi().\n\nDuring ipmi_add_smi(), the upper IPMI message handler obtains the\ninitial BMC device information through __bmc_get_device_id(). This can\nfail if the BMC does not return a successful response to the Get Device\nID command.\n\nWhen the BMC returns a nonzero completion code, the device-id helper\nretries the command and eventually returns -EIO if the device ID still\ncannot be fetched.\n\nOn this failure path, ipmi_add_smi() logs \"Unable to get the device id\"\nand goes to out_err_started, where it invokes the lower driver\u0027s\nshutdown callback. try_smi_init() then logs the returned registration\nfailure:\n\n ipmi_si IPI0001:00: IPMI message handler: Unable to get the device id: -5\n ipmi_si IPI0001:00: Unable to register device: error -5\n\nFor ipmi_si, the shutdown callback is shutdown_smi(), which cleans up\nthe SI state machine data, frees smi_info-\u003esi_sm, and sets\nsmi_info-\u003esi_sm and smi_info-\u003eintf to NULL.\n\nHowever, intf-\u003ein_shutdown is not set on this failed-registration\nrollback path. Therefore, the asynchronous redo_bmc_reg work item can\nstill retry BMC device-id probing after the lower driver has already\ncleared its SI state machine data. In the observed case, that retry path\nreached start_next_msg(), which passed the NULL smi_info-\u003esi_sm pointer\nto the selected KCS state machine handler:\n\nBUG: unable to handle kernel NULL pointer dereference at 0000000000000000\nWorkqueue: events redo_bmc_reg [ipmi_msghandler]\nRIP: start_kcs_transaction+0x2c/0x190 [ipmi_si]\nCall Trace:\n start_next_msg+0x50/0x80 [ipmi_si]\n check_start_timer_thread.part.9+0x3b/0x50 [ipmi_si]\n sender+0x69/0x80 [ipmi_si]\n i_ipmi_request+0x2ac/0x9d0 [ipmi_msghandler]\n __get_device_id.isra.29+0xaa/0x180 [ipmi_msghandler]\n __bmc_get_device_id+0xef/0x950 [ipmi_msghandler]\n redo_bmc_reg+0x52/0x60 [ipmi_msghandler]\n process_one_work+0x1a7/0x360\n\nSet intf-\u003ein_shutdown on the out_err_started path before invoking the\nlower driver\u0027s shutdown callback. This prevents later redo_bmc_reg\nretries from using an interface whose lower driver state has been\ncleaned up, and applies the same shutdown state to other IPMI interfaces\nas well.",
"id": "GHSA-36x4-6h38-8grw",
"modified": "2026-09-14T15:32:23Z",
"published": "2026-09-11T21:31:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81005"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/53af3a8bae0a93c1342e1b5519812203332aca8e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6d920a75df9a83ab096b3cde7a643b656e4fdfeb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/75ecc80ef0614a9f8441ab476fb748d3e919bea8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8ada17dd4c4ffd6b94621e735d77eda196ce118f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b11a1e545ad7a2f8f9ba7276b4ae9429c3399456"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d377bf743f29b41729a084a633874ef9c1a13c6a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d4be659a3e56f4eb16039ab8a1162efea086a714"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f390b0e781ca689515b659f94ef05f01497ed833"
}
],
"schema_version": "1.4.0",
"severity": []
}
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