# CVE-2026-81005

## Summary

- **CVE ID:** CVE-2026-81005
- **Severity:** UNKNOWN
- **CVSS Score:** 1.51
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 16, 2026

## Description

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 Products

- Linux — Linux (2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2)
- Linux — Linux (288bd736c8a027040fc261c86a87b65e7bc3f6fa)
- Linux — Linux (4.18.10)
- Linux — Linux (4.19)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/d4be659a3e56f4eb16039ab8a1162efea086a714)
- [CNA](https://git.kernel.org/stable/c/53af3a8bae0a93c1342e1b5519812203332aca8e)
- [CNA](https://git.kernel.org/stable/c/8ada17dd4c4ffd6b94621e735d77eda196ce118f)
- [CNA](https://git.kernel.org/stable/c/6d920a75df9a83ab096b3cde7a643b656e4fdfeb)
- [CNA](https://git.kernel.org/stable/c/75ecc80ef0614a9f8441ab476fb748d3e919bea8)
- [CNA](https://git.kernel.org/stable/c/b11a1e545ad7a2f8f9ba7276b4ae9429c3399456)
- [CNA](https://git.kernel.org/stable/c/f390b0e781ca689515b659f94ef05f01497ed833)
- [CNA](https://git.kernel.org/stable/c/d377bf743f29b41729a084a633874ef9c1a13c6a)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 7.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._