# CVE-2026-89486

## Summary

- **CVE ID:** CVE-2026-89486
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:

ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()

Commit 9e91f8a6c868 ("ipmi:msghandler: Remove srcu for the
ipmi_interfaces list") dropped the synchronize_rcu() between unlinking
the command receivers from intf->cmd_rcvrs and freeing them, updating
only the comment that explains why the barrier is needed.

The cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr()
walks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows
rcvr->user from that lookup within the same read-side section. Without
the grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a
reader still holds a pointer to it, causing a use-after-free.

The rework only made srcu unnecessary for the interfaces list; the
cmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu()
before freeing the receivers.

## Affected Products

- Linux — Linux (9e91f8a6c8688e27f4ccce7db457da87d6458836)
- Linux — Linux (6.16)
- Linux — Linux (0)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4)
- [CNA](https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5)
- [CNA](https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.12%
- **EPSS Percentile:** 2.4

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