# CVE-2023-52840: Input: synaptics-rmi4 - fix use after free in rmi\_unregister\_function()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.18

## Description

In the Linux kernel, the following vulnerability has been resolved: Input: synaptics-rmi4 - fix use after free in rmi_unregister_function() The put_device() calls rmi_release_function() which frees "fn" so the dereference on the next line "fn->num_of_irqs" is a use after free. Move the put_device() to the end to fix this.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/2f236d8638f5b43e0c72919a6a27fe286c32053f
- https://git.kernel.org/stable/c/50d12253666195a14c6cd2b81c376e2dbeedbdff
- https://git.kernel.org/stable/c/6c71e065befb2fae8f1461559b940c04e1071bd5
- https://git.kernel.org/stable/c/303766bb92c5c225cf40f9bbbe7e29749406e2f2
- https://git.kernel.org/stable/c/7082b1fb5321037bc11ba1cf2d7ed23c6b2b521f
- https://git.kernel.org/stable/c/cc56c4d17721dcb10ad4e9c9266e449be1462683
- https://git.kernel.org/stable/c/c8e639f5743cf4b01f8c65e0df075fe4d782b585
- https://git.kernel.org/stable/c/eb988e46da2e4eae89f5337e047ce372fe33d5b1

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Page: https://cve.now/CVE-2023-52840
JSON: https://cve.now/api/v1/entries/CVE-2023-52840
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