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Fencer Vulns
medium 5.5

CVE-2021-0938 json

In memzero_explicit of compiler-clang.h, there is a possible bypass of defense in depth due to uninitialized data.

published 2021-10-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-3557

cvss
5.5
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 4%
public exploits
0
none known

Summary

In memzero_explicit of compiler-clang.h, there is a possible bypass of defense in depth due to uninitialized data. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-171418586References: Upstream kernel

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.9.15-1

debian advisories DEBIAN-CVE-2021-0938

  • linux Ubuntu 20.04 LTS 5.4.0-66.74
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1038.40
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1037.40
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1036.38
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1033.34
  • linux-azure Ubuntu 20.04 LTS 5.4.0-1040.42
  • linux-gkeop Ubuntu 20.04 LTS 5.4.0-1010.11
  • linux-raspi Ubuntu 20.04 LTS 5.4.0-1029.32

ubuntu advisories UBUNTU-CVE-2021-0938

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

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-2021-0938 updated cvss 5.5

kernel: possible bypass of defense in depth due to uninitialized data in memzero_explicit() of compiler-clang.h

  • 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, kernel-alt, python-perf, +9 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

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • n/a Android

Classification

Weakness
  • CWE-908 Use of Uninitialized Resource

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.