Linux Kernel up to 6.19.12 input_ff_upload privilege escalation

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.19.12. The affected element is the function input_ff_upload. Executing a manipulation can lead to an unknown weakness. The identification of this vulnerability is CVE-2026-31667. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.19.12 and classified as critical. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: Input: uinput - fix circular locking dependency with ff-core A lockdep circular locking dependency warning can be triggered reproducibly when using a force-feedback gamepad with uinput (for example, playing ELDEN RING under Wine with a Flydigi Vader 5 controller): ff->mutex -> udev->mutex -> input_mutex -> dev->mutex -> ff->mutex The cycle is caused by four lock acquisition paths: 1. ff upload: input_ff_upload() holds ff->mutex and calls uinput_dev_upload_effect() -> uinput_request_submit() -> uinput_request_send(), which acquires udev->mutex. 2. device create: uinput_ioctl_handler() holds udev->mutex and calls uinput_create_device() -> input_register_device(), which acquires input_mutex. 3. device register: input_register_device() holds input_mutex and calls kbd_connect() -> input_register_handle(), which acquires dev->mutex. 4. evdev release: evdev_release() calls input_flush_device() under dev->mutex, which calls input_ff_flush() acquiring ff->mutex. Fix this by introducing a new state_lock spinlock to protect udev->state and udev->dev access in uinput_request_send() instead of acquiring udev->mutex. The function only needs to atomically check device state and queue an input event into the ring buffer via uinput_dev_event() -- both operations are safe under a spinlock (ktime_get_ts64() and wake_up_interruptible() do not sleep). This breaks the ff->mutex -> udev->mutex link since a spinlock is a leaf in the lock ordering and cannot form cycles with mutexes. To keep state transitions visible to uinput_request_send(), protect writes to udev->state in uinput_create_device() and uinput_destroy_device() with the same state_lock spinlock. Additionally, move init_completion(&request->done) from uinput_request_send() to uinput_request_submit() before uinput_request_reserve_slot(). Once the slot is allocated, uinput_flush_requests() may call complete() on it at any time from the destroy path, so the completion must be initialised before the request becomes visible. Lock ordering after the fix: ff->mutex -> state_lock (spinlock, leaf) udev->mutex -> state_lock (spinlock, leaf) udev->mutex -> input_mutex -> dev->mutex -> ff->mutex (no back-edge)

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-31667 since 03/09/2026. The exploitation appears to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/30/2026).

The vulnerability scanner Nessus provides a plugin with the ID 317729 (SUSE SLES12 Security Update : kernel (SUSE-SU-2026:2068-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.253, 5.15.203, 6.1.169, 6.6.135, 6.12.82, 6.18.23 or 6.19.13 eliminates this vulnerability. Applying the patch 71a9729f412e2c692a35c542e14b706fb342927f/271ee71a1917b89f6d73ec82dd091c33d92ee617/974f7b138c3a96dd5cd53d1b33409cd7b2229dc6/546c18a14924eb521fe168d916d7ce28f1e13c1d/a3d6c9c053c9c605651508569230ead633b13f76/1e09dfbb4f5d20ee111f92325a00f85778a5f328/1534661043c434b81cfde26b97a2fb2460329cf0/4cda78d6f8bf2b700529f2fbccb994c3e826d7c2 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (317729). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 317729
Nessus Name: SUSE SLES12 Security Update : kernel (SUSE-SU-2026:2068-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.253/5.15.203/6.1.169/6.6.135/6.12.82/6.18.23/6.19.13
Patch: 71a9729f412e2c692a35c542e14b706fb342927f/271ee71a1917b89f6d73ec82dd091c33d92ee617/974f7b138c3a96dd5cd53d1b33409cd7b2229dc6/546c18a14924eb521fe168d916d7ce28f1e13c1d/a3d6c9c053c9c605651508569230ead633b13f76/1e09dfbb4f5d20ee111f92325a00f85778a5f328/1534661043c434b81cfde26b97a2fb2460329cf0/4cda78d6f8bf2b700529f2fbccb994c3e826d7c2

Timelineinfo

03/09/2026 CVE reserved
04/24/2026 +45 days Advisory disclosed
04/24/2026 +0 days VulDB entry created
05/30/2026 +36 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31667 (🔒)
GCVE (CVE): GCVE-0-2026-31667
GCVE (VulDB): GCVE-100-359464

Entryinfo

Created: 04/24/2026 18:59
Updated: 05/30/2026 14:41
Changes: 04/24/2026 18:59 (57), 05/30/2026 14:41 (2)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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