Skip to content
Fencer Vulns
high 7.8

CVE-2021-39685 json

In various setup methods of the USB gadget subsystem, there is a possible out of bounds write due to an incorrect flag check.

published 2022-03-16 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26042

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

In various setup methods of the USB gadget subsystem, there is a possible out of bounds write due to an incorrect flag check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-210292376References: Upstream kernel

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.15.5-2

debian advisories DEBIAN-CVE-2021-39685

  • linux Ubuntu 18.04 LTS 4.15.0-169.177
  • linux Ubuntu 20.04 LTS 5.4.0-100.113
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1121.129
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1066.69
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1065.69
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1063.66
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1015.16
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1107.109

ubuntu advisories UBUNTU-CVE-2021-39685

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 SLE Micro 5.1, Real Time Module 15 SP3 5.3.18-150300.76.1
  • kernel-syms-rt Real Time Module 15 SP3 5.3.18-150300.76.1
  • kernel-rt_debug Real Time Module 15 SP3 5.3.18-150300.76.1
  • kernel-source-rt Real Time Module 15 SP3 5.3.18-150300.76.1
  • kernel-64kb SLE Module for Basesystem 15 SP3 5.3.18-150300.59.49.1
  • kernel-syms SLE Module for Development Tools 15 SP3 5.3.18-150300.59.49.1
  • kernel-source SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-150300.59.49.1
  • kernel-default SLE Workstation Extension 15 SP3, SLE Module for Legacy 15 SP3, SLE Module for Basesystem 15 SP3 +3 more 5.3.18-150300.59.49.1

suse advisories SUSE-SU-2022:0543-1SUSE-SU-2022:0370-1SUSE-SU-2022:0363-1

  • dtb-aarch64 openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-64kb openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-syms openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-obs-qa openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-source openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-default openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-preempt openSUSE Leap 15.3 5.3.18-150300.59.49.1
  • kernel-kvmsmall openSUSE Leap 15.3 5.3.18-150300.59.49.1

opensuse advisories openSUSE-SU-2022:0370-1openSUSE-SU-2022:0363-1

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-2021-39685 updated cvss 7.8

kernel: USB gadget buffer overflow

  • 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, +81 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

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • n/a Android

Classification

Weakness

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.