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Fencer Intel
medium 6.7

CVE-2021-0342 json

In tun_get_user of tun.c, there is possible memory corruption due to a use after free.

published 5y ago modified 4mo ago also EUVD-2021-2961

cvss
6.7
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 7%
public exploits
0
none known

Summary

In tun_get_user of tun.c, there is possible memory corruption due to a use after free. This could lead to local escalation of privilege with System execution privileges required. User interaction is not required for exploitation. Product: Android; Versions: Android kernel; Android ID: A-146554327.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.7.6-1

debian advisories DEBIAN-CVE-2021-0342

  • linux Ubuntu 18.04 LTS 4.15.0-115.116
  • linux Ubuntu 20.04 LTS 5.4.0-45.49
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1080.84
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1022.22
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1081.92~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1022.22
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-115.116~16.04.1
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1072.73

ubuntu advisories UBUNTU-CVE-2021-0342

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 RHEL 8 4.18.0-305.el8
  • perf RHEL 8 4.18.0-305.el8
  • bpftool RHEL 8 4.18.0-305.el8
  • kernel-core RHEL 8 4.18.0-305.el8
  • kernel-tools RHEL 8 4.18.0-305.el8
  • python3-perf RHEL 8 4.18.0-305.el8
  • kernel-modules RHEL 8 4.18.0-305.el8
  • kernel-zfcpdump RHEL 8 4.18.0-305.el8

red hat advisories RHSA-2021:1578RHSA-2021:1739

  • kernel-syms SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 4.12.14-197.83.1
  • kernel-source SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 4.12.14-197.83.1
  • kernel-default SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +8 more 4.12.14-197.83.1
  • kernel-zfcpdump SLES 15 SP1-LTSS, Manager Server 4.0 4.12.14-197.83.1
  • kernel-obs-build SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 4.12.14-197.83.1
  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.31.1
  • kernel-syms-rt SLE Real Time 12 SP5 4.12.14-10.31.1
  • kernel-rt_debug SLE Real Time 12 SP5 4.12.14-10.31.1

suse advisories SUSE-SU-2021:0853-1SUSE-SU-2021:0859-1SUSE-SU-2021:0818-1SUSE-SU-2021:0809-1SUSE-SU-2021:0849-1SUSE-SU-2021:0532-1

  • kernel-syms openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-obs-qa openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-source openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-default openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-preempt openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-kvmsmall openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-obs-build openSUSE Leap 15.2 5.3.18-lp152.63.1
  • kernel-default-base openSUSE Leap 15.2 5.3.18-lp152.63.1.lp152.8.21.1

opensuse advisories openSUSE-SU-2021:0241-1

Is CVE-2021-0342 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2021-0342 updated cvss 6.7

kernel: use after free in tun_get_user of tun.c could lead to local escalation of privilege

  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-305.el8, kernel-debuginfo-common-aarch64 4.18.0-305.el8, kernel-debuginfo-common-ppc64le 4.18.0-305.el8 Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-305.el8, kernel 4.18.0-305.el8, bpftool 4.18.0-305.el8, kernel-core 4.18.0-305.el8, kernel-tools 4.18.0-305.el8, python3-perf 4.18.0-305.el8, +15 more
    fixed: vendor fix RHSA-2021:1578
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-305.rt7.72.el8, kernel-rt-core 4.18.0-305.rt7.72.el8, kernel-rt-modules 4.18.0-305.rt7.72.el8, kernel-rt-debug-core 4.18.0-305.rt7.72.el8, kernel-rt-debug-modules 4.18.0-305.rt7.72.el8, kernel-rt-modules-extra 4.18.0-305.rt7.72.el8, +2 more Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-305.rt7.72.el8, kernel-rt-kvm 4.18.0-305.rt7.72.el8, kernel-rt-core 4.18.0-305.rt7.72.el8, kernel-rt-modules 4.18.0-305.rt7.72.el8, kernel-rt-debug-kvm 4.18.0-305.rt7.72.el8, kernel-rt-debug-core 4.18.0-305.rt7.72.el8, +4 more
    fixed: vendor fix RHSA-2021:1739
  • 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 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

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 6.7 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • n/a Android

Classification

Weakness

References

Sources

Fencer Intel 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.