CVE-2025-38556: linux kernel Out-of-bounds Read — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: HID: core: Harden s32ton() against conversion to 0 bits Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does.

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CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.20 — 6.12.46
linux	linux_kernel	6.13 — 6.15.10
linux	linux_kernel	6.16 — 6.16.1

References

Advisories & Patches

https://git.kernel.org/stable/c/865ad8469fa24de1559f247d9426ab01e5ce3a56 https://git.kernel.org/stable/c/8b4a94b1510f6a46ec48494b52ee8f67eb4fc836 https://git.kernel.org/stable/c/a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd https://git.kernel.org/stable/c/d3b504146c111548ab60b6ef7aad00bfb1db05a2

Other References

https://git.kernel.org/stable/c/3c86548a20d7bc2861aa4de044991a327bebad1a https://git.kernel.org/stable/c/6cdf6c708717c5c6897d0800a1793e83757c7491 https://git.kernel.org/stable/c/810189546cb6c8f36443ed091d91f1f5d2fc2ec7 https://git.kernel.org/stable/c/eeeaba737919bdce9885e2a00ac2912f61a3684d

Frequently Asked Questions

What is CVE-2025-38556? +

In the Linux kernel, the following vulnerability has been resolved: HID: core: Harden s32ton() against conversion to 0 bits Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2025-38556? +

CVE-2025-38556 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38556? +

CVE-2025-38556 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38556? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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