Bug 2351609 (CVE-2025-21856)

Summary: CVE-2025-21856 kernel: s390/ism: add release function for struct device
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-03-12 12:23:27 UTC 
In the Linux kernel, the following vulnerability has been resolved:

s390/ism: add release function for struct device

According to device_release() in /drivers/base/core.c,
a device without a release function is a broken device
and must be fixed.

The current code directly frees the device after calling device_add()
without waiting for other kernel parts to release their references.
Thus, a reference could still be held to a struct device,
e.g., by sysfs, leading to potential use-after-free
issues if a proper release function is not set.
Comment 1 Avinash Hanwate 2025-03-13 06:56:34 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025031215-CVE-2025-21856-8865@gregkh/T