CVE-2025-38682 Details
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.
A use-after-free vulnerability has been identified in the Linux kernel's I2C core, specifically within the `i2c_unregister_device()` function. This issue arises from a double-free of the firmware node (fwnode) reference. The vulnerability was introduced in a previous commit that changed how fwnode references are managed during device unregistration. When an I2C client lacks a primary fwnode but has a software fwnode, the software fwnode is incorrectly treated as the primary node. This mismanagement leads to the software fwnode being freed twice, causing a reference count underflow and a subsequent use-after-free condition.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. Instructions for upgrading the Linux kernel can be found in the official Linux kernel documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/1c24e5fc0c7096e00c202a6a3e0c342c1afb47c2 | kernel.org | Patch |
| https://git.kernel.org/stable/c/ffe02f7c4e36090154646612e67d331832f92037 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-415 | Double Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.16, < 6.16.2 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| Nov 25, 2025 | Initial Analysis | [email protected] |
| Sep 4, 2025 | New CVE Received | kernel.org |