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Fencer Vulns
high 7.8

CVE-2022-48822 json

usb: f_fs: Fix use-after-free for epfile

published 2024-07-16 2 y ago modified 2026-08-05 3 mo ago also EUVD-2022-53701

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 4.9, 4.14.267, 4.19.230, 5.4.180, 5.10.101, 5.15.24, 5.16.10, 5.17
  • linux Debian 14, Debian 13, Debian 12 5.16.10-1

debian advisories DEBIAN-CVE-2022-48822

  • linux Ubuntu 18.04 LTS 4.15.0-177.186
  • linux Ubuntu 20.04 LTS 5.4.0-110.124
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1128.137
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1073.78
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1073.78
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1021.23
  • linux-iot Ubuntu 20.04 LTS 5.4.0-1004.6
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1114.117

ubuntu advisories UBUNTU-CVE-2022-48822

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-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.197.1
  • kernel-syms-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.197.1
  • kernel-source-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.197.1
  • kernel-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.228.1
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.228.1
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.228.1
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.228.2
  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.200.1

suse advisories SUSE-SU-2024:3252-1SUSE-SU-2024:3251-1SUSE-SU-2024:3189-1SUSE-SU-2024:2948-1SUSE-SU-2024:2947-1SUSE-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-2022-48822 updated cvss 4.4

kernel: usb: f_fs: Fix use-after-free for epfile

  • 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 SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 20% 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
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

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.