high 7.8

CVE-2024-36894 json

usb: gadget: f_fs: Fix race between aio_cancel() and AIO request complete

published 2024-05-30 2 y ago modified 2026-10-15 25 d ago also EUVD-2024-36246

cvss: 7.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits: 0; none known

In the Linux kernel, the following vulnerability has been resolved:

FFS based applications can utilize the aio_cancel() callback to dequeue pending USB requests submitted to the UDC. There is a scenario where the FFS application issues an AIO cancel call, while the UDC is handling a soft disconnect. For a DWC3 based implementation, the callstack looks like the following:

DWC3 Gadget FFS Application dwc3_gadget_soft_disconnect() ... --> dwc3_stop_active_transfers() --> dwc3_gadget_giveback(-ESHUTDOWN) --> ffs_epfile_async_io_complete() ffs_aio_cancel() --> usb_ep_free_request() --> usb_ep_dequeue()

There is currently no locking implemented between the AIO completion handler and AIO cancel, so the issue occurs if the completion routine is running in parallel to an AIO cancel call coming from the FFS application. As the completion call frees the USB request (io_data->req) the FFS application is also referencing it for the usb_ep_dequeue() call. This can lead to accessing a stale/hanging pointer.

commit b566d38857fc ("usb: gadget: f_fs: use io_data->status consistently") relocated the usb_ep_free_request() into ffs_epfile_async_io_complete(). However, in order to properly implement locking to mitigate this issue, the spinlock can't be added to ffs_epfile_async_io_complete(), as usb_ep_dequeue() (if successfully dequeuing a USB request) will call the function driver's completion handler in the same context. Hence, leading into a deadlock.

Fix this issue by moving the usb_ep_free_request() back to ffs_user_copy_worker(), and ensuring that it explicitly sets io_data->req to NULL after freeing it within the ffs->eps_lock. This resolves the race condition above, as the ffs_aio_cancel() routine will not continue attempting to dequeue a request that has already been freed, or the ffs_user_copy_work() not freeing the USB request until the AIO cancel is done referencing it.

This fix depends on commit b566d38857fc ("usb: gadget: f_fs: use io_data->status consistently")

Patch / fix

fixed in 3 distros 3 links 8

Linux Linux 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.95, 6.6.31, 6.8.10, 6.9
linux linux_kernel 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.95, 6.6.31, 6.8.10, 6.9, 9e72ef59cbe6, 73c05ad46bb4, 3613e5023f09, 24729b307eef, a0fdccb1c9e0, d74618308232, e500b1c4e29a, f71a53148ce3
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem V1.1.1

debian ubuntu suse

linux Debian 12 6.1.99-1
linux Debian 14, Debian 13 6.8.11-1

debian advisories DEBIAN-CVE-2024-36894

linux Ubuntu 20.04 LTS 5.4.0-195.215
linux Ubuntu 22.04 LTS 5.15.0-121.131
linux Ubuntu 24.04 LTS 6.8.0-40.40
linux-aws Ubuntu 20.04 LTS 5.4.0-1132.142
linux-aws Ubuntu 22.04 LTS 5.15.0-1069.75
linux-aws Ubuntu 24.04 LTS 6.8.0-1013.14
linux-gcp Ubuntu 20.04 LTS 5.4.0-1136.145
linux-gcp Ubuntu 22.04 LTS 5.15.0-1068.76

ubuntu advisories UBUNTU-CVE-2024-36894

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-livepatch-MICRO-6-0-RT_Update_5 Linux Micro 6.1, Linux Micro 6.0 1-1.1
kernel-rt Linux Micro 6.0 6.4.0-9.1
kernel-source-rt Linux Micro 6.0 6.4.0-9.1
kernel-source Linux Micro 6.0 6.4.0-18.1
kernel-default Linux Micro 6.0 6.4.0-18.1
kernel-kvmsmall Linux Micro 6.0 6.4.0-18.1

suse advisories SUSE-SU-2025:20166-1 SUSE-SU-2025:20249-1 SUSE-SU-2025:20028-1 SUSE-SU-2025:20008-1 SUSE-SU-2024:2973-1 SUSE-SU-2024:2939-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-36894 updated 2026-11-06 cvss 4.4

kernel: usb: gadget: f_fs: Fix race between aio_cancel() and AIO request complete

Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-24-102-01 updated 2026-05-14 cvss 4.4

Siemens SIMATIC S7-1500 TM MFP

Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-25-226-07 updated 2026-02-25

Siemens Third-Party Components in SINEC OS

Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family
not affected

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-06-03)

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA ADP	3.1	5.6	CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
CNA	3.1	5.6	CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

Linux Linux
linux linux_kernel
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2024-36894
NVD CVE-2024-36894

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary