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Fencer Vulns
high 7.8

CVE-2020-27786 json

A flaw was found in the Linux kernel’s implementation of MIDI, where an attacker with a local account and the permissions to issue ioctl co…

published 2020-12-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20288

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

A flaw was found in the Linux kernel’s implementation of MIDI, where an attacker with a local account and the permissions to issue ioctl commands to midi devices could trigger a use-after-free issue. A write to this specific memory while freed and before use causes the flow of execution to change and possibly allow for memory corruption or privilege escalation. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Patch / fix

  • linux linux_kernel 4.4.224, 4.9.224, 4.14.181, 4.19.124, 5.4.42, 5.6.14
  • linux Debian 14, Debian 13, Debian 12 5.6.14-1

debian advisories DEBIAN-CVE-2020-27786

  • linux Ubuntu 16.04 LTS 4.4.0-185.215
  • linux Ubuntu 18.04 LTS 4.15.0-109.110
  • linux Ubuntu 20.04 LTS 5.4.0-40.44
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1110.121
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1077.81
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1018.18
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1078.88~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1019.19

ubuntu advisories UBUNTU-CVE-2020-27786

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

  • kgraft-patch-SLE12-SP2_Update_36 SLES for SAP 12 SP2, SLES 12 SP2-LTSS, OpenStack Cloud 7 7-2.2
  • kernel-syms SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.138.1
  • kernel-source SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.138.1
  • kernel-default SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +5 more 4.4.180-94.138.1
  • kgraft-patch-SLE12-SP3_Update_37 SLES for SAP 12 SP3, SLES 12 SP3-LTSS, OpenStack Cloud Crowbar 8 +3 more 1-4.3.1
  • kernel-syms SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 4.12.14-150.66.1
  • kernel-source SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 4.12.14-150.66.1
  • kernel-default SLES for SAP 15, SLES 15-LTSS, SLE Live Patching 15 +3 more 4.12.14-150.66.1

suse advisories SUSE-SU-2021:0868-1SUSE-SU-2021:0853-1SUSE-SU-2021:0859-1SUSE-SU-2021:0818-1SUSE-SU-2021:0809-1SUSE-SU-2021:0870-1

  • kernel-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-syms-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-rt_debug openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-source-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-syms openSUSE Leap 15.1 4.12.14-lp151.28.91.1
  • kernel-obs-qa openSUSE Leap 15.1 4.12.14-lp151.28.91.1
  • kernel-source openSUSE Leap 15.1 4.12.14-lp151.28.91.1
  • kernel-default openSUSE Leap 15.1 4.12.14-lp151.28.91.1

opensuse advisories openSUSE-SU-2021:0242-1openSUSE-SU-2021:0075-1openSUSE-SU-2021:0060-1

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-2020-27786 updated cvss 7.8

kernel: use-after-free in kernel midi subsystem

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, kernel-alt, python-perf, +9 more
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    affected: workaround, no fix planned “Out of support scope”
  • 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 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 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

1.67% chance of exploitation in the next 30 days, higher than 76% 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 kernel

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.