CVE-2022-48822: In the Linux kernel, the following vulnerability has been resolved: usb: f_fs: Fix use-after-free for epfile Consider a case where ffs_func_eps_disa...

Description

In the Linux kernel, the following vulnerability has been resolved: usb: f_fs: Fix use-after-free for epfile Consider a case where ffs_func_eps_disable is called from ffs_func_disable as part of composition switch and at the same time ffs_epfile_release get called from userspace. ffs_epfile_release will free up the read buffer and call ffs_data_closed which in turn destroys ffs->epfiles and mark it as NULL. While this was happening the driver has already initialized the local epfile in ffs_func_eps_disable which is now freed and waiting to acquire the spinlock. Once spinlock is acquired the driver proceeds with the stale value of epfile and tries to free the already freed read buffer causing use-after-free. Following is the illustration of the race: CPU1 CPU2 ffs_func_eps_disable epfiles (local copy) ffs_epfile_release ffs_data_closed if (last file closed) ffs_data_reset ffs_data_clear ffs_epfiles_destroy spin_lock dereference epfiles Fix this races by taking epfiles local copy & assigning it under spinlock and if epfiles(local) is null then update it in ffs->epfiles then finally destroy it. Extending the scope further from the race, protecting the ep related structures, and concurrent accesses.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.27%

18.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 4.9, < 4.14.267
Linux	Linux Kernel	>= 4.15, < 4.19.230
Linux	Linux Kernel	>= 4.20, < 5.4.180
Linux	Linux Kernel	>= 5.5, < 5.10.101
Linux	Linux Kernel	>= 5.11, < 5.15.24
Linux	Linux Kernel	>= 5.16, < 5.16.10

References

Timeline

Published: Jul 16, 2024
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-48822?

In the Linux kernel, the following vulnerability has been resolved: usb: f_fs: Fix use-after-free for epfile Consider a case where ffs_func_eps_disable is called from ffs_func_disable as part of composition switch and at the same time ffs_epfile_release get called from userspace. ffs_epfile_release will free up the read buffer and call ffs_data_closed which in turn destroys ffs->epfiles and mark it as NULL. While this was happening the driver has already initialized the local epfile in ffs_func_eps_disable which is now freed and waiting to acquire the spinlock. Once spinlock is acquired the driver proceeds with the stale value of epfile and tries to free the already freed read buffer causing use-after-free. Following is the illustration of the race: CPU1 CPU2 ffs_func_eps_disable epfiles (local copy) ffs_epfile_release ffs_data_closed if (last file closed) ffs_data_reset ffs_data_clear ffs_epfiles_destroy spin_lock dereference epfiles Fix this races by taking epfiles local copy & assigning it under spinlock and if epfiles(local) is null then update it in ffs->epfiles then finally destroy it. Extending the scope further from the race, protecting the ep related structures, and concurrent accesses.

How severe is CVE-2022-48822?

CVE-2022-48822 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.27% probability of exploitation in the next 30 days.

How do I fix CVE-2022-48822?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.