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Fencer Vulns
medium 4.1

CVE-2021-39648 json

In gadget_dev_desc_UDC_show of configfs.c, there is a possible disclosure of kernel heap memory due to a race condition.

published 2021-12-15 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26005

cvss
4.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

In gadget_dev_desc_UDC_show of configfs.c, there is a possible disclosure of kernel heap memory due to a race condition. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-160822094References: Upstream kernel

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.10.9-1

debian advisories DEBIAN-CVE-2021-39648

  • linux Ubuntu 18.04 LTS 4.15.0-137.141
  • linux Ubuntu 20.04 LTS 5.4.0-67.75
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1095.102
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1039.41
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1094.107~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1038.41
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1037.39
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-137.141~16.04.1

ubuntu advisories UBUNTU-CVE-2021-39648

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 Real Time 12 SP5 4.12.14-10.78.1
  • kernel-syms-rt SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-rt_debug SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-source-rt SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-rt SLE Micro 5.0, Real Time Module 15 SP2 5.3.18-73.1
  • kernel-syms-rt Real Time Module 15 SP2 5.3.18-73.1
  • kernel-rt_debug Real Time Module 15 SP2 5.3.18-73.1
  • kernel-source-rt Real Time Module 15 SP2 5.3.18-73.1

suse advisories SUSE-SU-2022:0555-1SUSE-SU-2022:0544-1SUSE-SU-2022:0543-1SUSE-SU-2022:0477-1SUSE-SU-2022:0372-1SUSE-SU-2022:0371-1

  • 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-2022:0366-1openSUSE-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-2021-39648 updated cvss 4.1

kernel: possible disclosure of memory due to a race condition in gadget_dev_desc_UDC_show() of configfs.c

  • 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, +82 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

0.17% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.1 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 1.9 AV:L/AC:M/Au:N/C:P/I:N/A:N

Affected products

  • n/a Android

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

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.