CVE-2025-38682: i2c: core: Fix double-free of fwnode in i2c_unregister_device()
In the Linux kernel, the following vulnerability has been resolved:
i2c: core: Fix double-free of fwnode in i2cunregisterdevice()
Before commit df6d7277e552 ("i2c: core: Do not dereference fwnode in struct device"), i2cunregisterdevice() only called fwnodehandleput() on ofnode-s in the form of calling ofnodeput(client->dev.ofnode).
But after this commit the i2cclient's fwnode now unconditionally gets fwnodehandleput() on it.
When the i2cclient has no primary (ACPI / OF) fwnode but it does have a software fwnode, the software-node will be the primary node and fwnodehandleput() will put() it.
But for the software fwnode deviceremovesoftwarenode() will also put() it leading to a double free:
[ 82.665598] ------------[ cut here ]------------ [ 82.665609] refcountt: underflow; use-after-free. [ 82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcountwarnsaturate+0xba/0x11 ... [ 82.666830] RIP: 0010:refcountwarnsaturate+0xba/0x110 ... [ 82.666962] <TASK> [ 82.666971] i2cunregisterdevice+0x60/0x90
Fix this by not calling fwnodehandleput() when the primary fwnode is a software-node.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-38682?
CVE-2025-38682 has a moderate severity level due to potential double-free vulnerabilities in the Linux kernel.
How do I fix CVE-2025-38682?
You can fix CVE-2025-38682 by upgrading to a Linux kernel version beyond df6d7277e552.
Which systems are affected by CVE-2025-38682?
CVE-2025-38682 affects Linux kernel versions prior to df6d7277e552.
What components are involved in the CVE-2025-38682 vulnerability?
The vulnerability is related to the i2c core component in the Linux kernel.
Is there a patch available for CVE-2025-38682?
Yes, a patch is included in subsequent Linux kernel releases after the problematic commit.