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

i2c: core: Fix double-free of fwnode in i2c_unregister_device()

Before commit df6d7277e552 ("i2c: core: Do not dereference fwnode in struct
device"), i2c_unregister_device() only called fwnode_handle_put() on
of_node-s in the form of calling of_node_put(client->dev.of_node).

But after this commit the i2c_client's fwnode now unconditionally gets
fwnode_handle_put() on it.

When the i2c_client has no primary (ACPI / OF) fwnode but it does have
a software fwnode, the software-node will be the primary node and
fwnode_handle_put() will put() it.

But for the software fwnode device_remove_software_node() will also put()
it leading to a double free:

[ 82.665598] ------------[ cut here ]------------
[ 82.665609] refcount_t: underflow; use-after-free.
[ 82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x11
...
[ 82.666830] RIP: 0010:refcount_warn_saturate+0xba/0x110
...
[ 82.666962] <TASK>
[ 82.666971] i2c_unregister_device+0x60/0x90

Fix this by not calling fwnode_handle_put() when the primary fwnode is
a software-node.
History

Fri, 05 Sep 2025 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Fri, 05 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Thu, 04 Sep 2025 15:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: i2c: core: Fix double-free of fwnode in i2c_unregister_device() Before commit df6d7277e552 ("i2c: core: Do not dereference fwnode in struct device"), i2c_unregister_device() only called fwnode_handle_put() on of_node-s in the form of calling of_node_put(client->dev.of_node). But after this commit the i2c_client's fwnode now unconditionally gets fwnode_handle_put() on it. When the i2c_client has no primary (ACPI / OF) fwnode but it does have a software fwnode, the software-node will be the primary node and fwnode_handle_put() will put() it. But for the software fwnode device_remove_software_node() will also put() it leading to a double free: [ 82.665598] ------------[ cut here ]------------ [ 82.665609] refcount_t: underflow; use-after-free. [ 82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x11 ... [ 82.666830] RIP: 0010:refcount_warn_saturate+0xba/0x110 ... [ 82.666962] <TASK> [ 82.666971] i2c_unregister_device+0x60/0x90 Fix this by not calling fwnode_handle_put() when the primary fwnode is a software-node.
Title i2c: core: Fix double-free of fwnode in i2c_unregister_device()
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-09-04T15:32:37.403Z

Reserved: 2025-04-16T04:51:24.031Z

Link: CVE-2025-38682

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-04T16:15:35.910

Modified: 2025-09-05T17:47:24.833

Link: CVE-2025-38682

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-04T00:00:00Z

Links: CVE-2025-38682 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-09-05T14:02:52Z