CVE-2026-45885
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Use-After-Free in Linux Kernel CPCAP Battery Driver

Publication date: 2026-05-27

Last updated on: 2026-05-27

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: power: supply: cpcap-battery: Fix use-after-free in power_supply_changed() Using the `devm_` variant for requesting IRQ _before_ the `devm_` variant for allocating/registering the `power_supply` handle, means that the `power_supply` handle will be deallocated/unregistered _before_ the interrupt handler (since `devm_` naturally deallocates in reverse allocation order). This means that during removal, there is a race condition where an interrupt can fire just _after_ the `power_supply` handle has been freed, *but* just _before_ the corresponding unregistration of the IRQ handler has run. This will lead to the IRQ handler calling `power_supply_changed()` with a freed `power_supply` handle. Which usually crashes the system or otherwise silently corrupts the memory... Note that there is a similar situation which can also happen during `probe()`; the possibility of an interrupt firing _before_ registering the `power_supply` handle. This would then lead to the nasty situation of using the `power_supply` handle *uninitialized* in `power_supply_changed()`. Fix this racy use-after-free by making sure the IRQ is requested _after_ the registration of the `power_supply` handle.
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Meta Information
Published
2026-05-27
Last Modified
2026-05-27
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-15
NVD
CVE-2026-45885
EUVD
EUVD-2026-32351
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux_kernel power_supply *
linux kernel *
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Exploitability
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KEV
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's power supply subsystem, specifically in the cpcap-battery driver. It is a use-after-free bug caused by the order in which resources are allocated and freed.

The issue arises because the interrupt request (IRQ) is requested before the power_supply handle is allocated and registered. Since the devm_ (device-managed) functions free resources in reverse order of allocation, the power_supply handle can be freed before the IRQ handler is unregistered.

This creates a race condition during device removal where an interrupt can trigger after the power_supply handle has been freed but before the IRQ handler is unregistered. As a result, the IRQ handler calls power_supply_changed() with a freed handle, which can crash the system or corrupt memory.

A similar problem can occur during device probe if an interrupt fires before the power_supply handle is registered, causing the handler to use an uninitialized handle.

The fix involves changing the order so that the IRQ is requested only after the power_supply handle has been registered, preventing the use-after-free condition.

Impact Analysis

This vulnerability can lead to system instability or crashes because the interrupt handler may access memory that has already been freed.

It can also cause silent memory corruption, which might lead to unpredictable behavior or security issues in the affected system.

Since this occurs in the power supply subsystem, it could affect battery management or power-related functions on devices using the vulnerable Linux kernel.

Mitigation Strategies

The vulnerability is caused by a race condition in the Linux kernel power supply subsystem, specifically in the cpcap-battery driver, where the IRQ handler can access a freed or uninitialized power_supply handle.

To mitigate this vulnerability, ensure that the IRQ is requested only after the power_supply handle has been registered. This prevents the use-after-free condition by maintaining the correct allocation and deallocation order.

Practically, this means updating or patching the Linux kernel to the fixed version where the IRQ request order has been corrected.

Compliance Impact

The provided information does not include any details about the impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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