Summary
In the Linux kernel, the following vulnerability has been resolved: HID: asus: fix UAF via...
In the Linux kernel, the following vulnerability has been resolved:
HID: asus: fix UAF via HID_CLAIMED_INPUT validation
After hid_hw_start() is called hidinput_connect() will eventually be
called to set up the device with the input layer since the
HID_CONNECT_DEFAULT connect mask is used. During hidinput_connect()
all input and output reports are processed and corresponding hid_inputs
are allocated and configured via hidinput_configure_usages(). This
process involves slot tagging report fields and configuring usages
by setting relevant bits in the capability bitmaps. However it is possible
that the capability bitmaps are not set at all leading to the subsequent
hidinput_has_been_populated() check to fail leading to the freeing of the
hid_input and the underlying input device.
This becomes problematic because a malicious HID device like a
ASUS ROG N-Key keyboard can trigger the above scenario via a
specially crafted descriptor which then leads to a user-after-free
when the name of the freed input device is written to later on after
hid_hw_start(). Below, report 93 intentionally utilises the
HID_UP_UNDEFINED Usage Page which is skipped during usage
configuration, leading to the frees.
0x05, 0x0D, // Usage Page (Digitizer)
0x09, 0x05, // Usage (Touch Pad)
0xA1, 0x01, // Collection (Application)
0x85, 0x0D, // Report ID (13)
0x06, 0x00, 0xFF, // Usage Page (Vendor Defined 0xFF00)
0x09, 0xC5, // Usage (0xC5)
0x15, 0x00, // Logical Minimum (0)
0x26, 0xFF, 0x00, // Logical Maximum (255)
0x75, 0x08, // Report Size (8)
0x95, 0x04, // Report Count (4)
0xB1, 0x02, // Feature (Data,Var,Abs)
0x85, 0x5D, // Report ID (93)
0x06, 0x00, 0x00, // Usage Page (Undefined)
0x09, 0x01, // Usage (0x01)
0x15, 0x00, // Logical Minimum (0)
0x26, 0xFF, 0x00, // Logical Maximum (255)
0x75, 0x08, // Report Size (8)
0x95, 0x1B, // Report Count (27)
0x81, 0x02, // Input (Data,Var,Abs)
0xC0, // End Collection
Below is the KASAN splat after triggering the UAF:
[ 21.672709] ==================================================================
[ 21.673700] BUG: KASAN: slab-use-after-free in asus_probe+0xeeb/0xf80
[ 21.673700] Write of size 8 at addr ffff88810a0ac000 by task kworker/1:2/54
[ 21.673700]
[ 21.673700] CPU: 1 UID: 0 PID: 54 Comm: kworker/1:2 Not tainted 6.16.0-rc4-g9773391cf4dd-dirty #36 PREEMPT(voluntary)
[ 21.673700] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 21.673700] Call Trace:
[ 21.673700]
[ 21.673700] dump_stack_lvl+0x5f/0x80
[ 21.673700] print_report+0xd1/0x660
[ 21.673700] kasan_report+0xe5/0x120
[ 21.673700] __asan_report_store8_noabort+0x1b/0x30
[ 21.673700] asus_probe+0xeeb/0xf80
[ 21.673700] hid_device_probe+0x2ee/0x700
[ 21.673700] really_probe+0x1c6/0x6b0
[ 21.673700] __driver_probe_device+0x24f/0x310
[ 21.673700] driver_probe_device+0x4e/0x220
[...]
[ 21.673700]
[ 21.673700] Allocated by task 54:
[ 21.673700] kasan_save_stack+0x3d/0x60
[ 21.673700] kasan_save_track+0x18/0x40
[ 21.673700] kasan_save_alloc_info+0x3b/0x50
[ 21.673700] __kasan_kmalloc+0x9c/0xa0
[ 21.673700] __kmalloc_cache_noprof+0x139/0x340
[ 21.673700] input_allocate_device+0x44/0x370
[ 21.673700] hidinput_connect+0xcb6/0x2630
[ 21.673700] hid_connect+0xf74/0x1d60
[ 21.673700] hid_hw_start+0x8c/0x110
[ 21.673700] asus_probe+0x5a3/0xf80
[ 21.673700] hid_device_probe+0x2ee/0x700
[ 21.673700] really_probe+0x1c6/0x6b0
[ 21.673700] __driver_probe_device+0x24f/0x310
[ 21.673700] driver_probe_device+0x4e/0x220
[...]
[ 21.673700]
[ 21.673700] Freed by task 54:
[ 21.673700] kasan_save_stack+0x3d/0x60
[ 21.673700] kasan_save_track+0x18/0x40
[ 21.673700] kasan_save_free_info+0x3f/0x60
[ 21.673700] __kasan_slab_free+0x3c/0x50
[ 21.673700] kfre
---truncated---
Impact
Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.
CVE-2025-39824 has a CVSS score of 7.8 (High). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-39824? CVE-2025-39824 is a high-severity use after free vulnerability. No fixed version is listed yet. Memory is accessed after it has been freed, leading to undefined behavior in native code.
- How severe is CVE-2025-39824? CVE-2025-39824 has a CVSS score of 7.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-39824? No fixed version is listed for CVE-2025-39824 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-39824 exploitable, and should I be worried? Whether CVE-2025-39824 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-39824 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.