Linux KernelOperating system · Linux
CVE-2025-38557
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn the Linux kernel, the following vulnerability has been resolved: HID: apple: validate feature-report field count to prevent NULL pointer dereference A malicious HID device with quirk APPLE_MAGIC_BACKLIGHT can trigger a NULL pointer dereference whilst the power feature-report is toggled and sent to the device in apple_magic_backlight_report_set(). The power feature-report is expected to have two data fields, but if the descriptor declares one field then accessing field[1] and dereferencing it in apple_magic_backlight_report_set() becomes invalid since field[1] will be NULL. An example of a minimal descriptor which can cause the crash is something like the following where the report with ID 3 (power report) only references a single 1-byte field. When hid core parses the descriptor it will encounter the final feature tag, allocate a hid_report (all members of field[] will be zeroed out), create field structure and populate it, increasing the maxfield to 1. The subsequent field[1] access and dereference causes the crash. Usage Page (Vendor Defined 0xFF00) Usage (0x0F) Collection (Application) Report ID (1) Usage (0x01) Logical Minimum (0) Logical Maximum (255) Report Size (8) Report Count (1) Feature (Data,Var,Abs) Usage (0x02) Logical Maximum (32767) Report Size (16) Report Count (1) Feature (Data,Var,Abs) Report ID (3) Usage (0x03) Logical Minimum (0) Logical Maximum (1) Report Size (8) Report Count (1) Feature (Data,Var,Abs) End Collection Here we see the KASAN splat when the kernel dereferences the NULL pointer and crashes: [ 15.164723] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN NOPTI [ 15.165691] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] [ 15.165691] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.15.0 #31 PREEMPT(voluntary) [ 15.165691] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 [ 15.165691] RIP: 0010:apple_magic_backlight_report_set+0xbf/0x210 [ 15.165691] Call Trace: [ 15.165691] <TASK> [ 15.165691] apple_probe+0x571/0xa20 [ 15.165691] hid_device_probe+0x2e2/0x6f0 [ 15.165691] really_probe+0x1ca/0x5c0 [ 15.165691] __driver_probe_device+0x24f/0x310 [ 15.165691] driver_probe_device+0x4a/0xd0 [ 15.165691] __device_attach_driver+0x169/0x220 [ 15.165691] bus_for_each_drv+0x118/0x1b0 [ 15.165691] __device_attach+0x1d5/0x380 [ 15.165691] device_initial_probe+0x12/0x20 [ 15.165691] bus_probe_device+0x13d/0x180 [ 15.165691] device_add+0xd87/0x1510 [...] To fix this issue we should validate the number of fields that the backlight and power reports have and if they do not have the required number of fields then bail.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisThe code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.
General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 6.11, < 6.12.42>= 6.13, < 6.15.10>= 6.16, < 6.16.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped6.12.426.15.106.16.1
6.12.42 (for 6.11-6.12.x) | 6.15.10 (for 6.13-6.15.x) | 6.16.1 (for 6.16.x)
- Upgrade Linux kernel to version 6.12.42 or later if running kernel 6.11.x through 6.12.x
- Upgrade Linux kernel to version 6.15.10 or later if running kernel 6.13.x through 6.15.x
- Upgrade Linux kernel to version 6.16.1 or later if running kernel 6.16.x
- After kernel upgrade, reboot the system to load the fixed kernel version
- Verify the fix is active by checking kernel version: uname -r
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-38557 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-38557 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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