CVE-2026-89486 - Vulnerability Details

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

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.

Published: 2026-09-11

Score: 7.8 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The Linux kernel cmd_rcvr structures to be freed while still referenced by reader threads. This use‑after‑free can be triggered when an IPMI user is destroyed while a concurrent request is in flight, leading the kernel to dereference freed memory. An attacker who can stimulate this scenario could execute arbitrary code at kernel privilege, compromising confidentiality, integrity, and availability.

Affected Systems

All installations of the Linux kernel that contain the legacy IPMI interface code without the fix that restores the synchronize_rcu() call before freeing cmd_rcvs are vulnerable. Every distribution that ships those kernel versions is affected. No specific version numbers are listed, so any kernel containing.

Risk and Exploitability

The CVSS score is 6.5, indicating medium severity. The EPSS score is < 1%, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector is remote root‑level access to IPMI commands can create concurrent requests that trigger the flaw. Successful exploitation requires the ability to invoke IPMI commands and cause the victim to free it while a reader still holds a reference.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`9e91f8a6c8688e27f4ccce7db457da87d6458836`	affected	< 3088e41292fecf132f85f79af5ee4d620b9ff1b4
`9e91f8a6c8688e27f4ccce7db457da87d6458836`	affected	< 5dc0b2a9af95a97861c1bffaf1687a3173e395c5
`9e91f8a6c8688e27f4ccce7db457da87d6458836`	affected	< 05ec76cfbce653e07cec19b9b8b20e33449d5d87

Linux

affected

Version	Status	Constraints
`6.16`	affected	—
`0`	unaffected	< 6.16
`6.18.50`	unaffected	≤ 6.18.*
`7.2.4`	unaffected	≤ 7.2.*
`7.3-rc1`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[9e91f8a6c8688e27f4ccce7db457da87d6458836,3088e41292fecf132f85f79af5ee4d620b9ff1b4)`	affected	code_commit	—
`[9e91f8a6c8688e27f4ccce7db457da87d6458836,5dc0b2a9af95a97861c1bffaf1687a3173e395c5)`	affected	code_commit	—
`[9e91f8a6c8688e27f4ccce7db457da87d6458836,05ec76cfbce653e07cec19b9b8b20e33449d5d87)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`6.16`	affected	generic	—
`[0,6.16)`	unaffected	generic	—
`[6.18.50,6.19.0)`	unaffected	semver	—
`[7.2.4,7.3.0)`	unaffected	semver	—
`[7.3-rc1,*]`	unaffected	semver	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Apply a kernel update that includes commit 9e91 restores the synchronize_rcu() barrier before freeing cmd_rcvs.
If the IPMI subsystem is not required for the system’s operation, disable the IPMI module or kernel support to remove the attack surface.
If IPMI must remain enabled, restrict its network exposure by configuring firewalls or network isolation so that only trusted hosts can access the BMC.

Generated by OpenCVE AI on September 13, 2026 at 02:11 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00166.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87
https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4
https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5
https://nvd.nist.gov/vuln/detail/CVE-2026-89486
https://www.cve.org/CVERecord?id=CVE-2026-89486

History

Sun, 13 Sep 2026 06:45:00 +0000

Type	Values Removed	Values Added
Metrics	cvssV3_1 `{'score': 6.5, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:H'}`	cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`

Sat, 12 Sep 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-825
References		https://nvd.nist.gov/vuln/detail/CVE-2026-89486 https://www.cve.org/CVERecord?id=CVE-2026-89486
Metrics	threat_severity `None`	cvssV3_1 `{'score': 6.5, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:H'}` threat_severity `Moderate`

Fri, 11 Sep 2026 23:45:00 +0000

Type	Values Removed	Values Added
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.
Title		ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87 https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4 https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-09-11T19:43:40.116Z

Updated: 2026-09-13T06:29:55.269Z

Reserved: 2026-09-11T19:38:34.712Z

Link: CVE-2026-89486

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-09-11T20:19:30.297

Modified: 2026-09-13T07:17:11.900

Link: CVE-2026-89486

Redhat

Severity : Moderate

Publid Date: 2026-09-11T19:43:40Z

Links: CVE-2026-89486 - Bugzilla

OpenCVE Enrichment

Updated: 2026-09-13T02:15:17Z

Weaknesses

CWE-825
Expired Pointer Dereference

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object