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Fencer Vulns
medium 5.5

CVE-2020-27830 json

A vulnerability was found in Linux Kernel where in the spk_ttyio_receive_buf2() function, it would dereference spk_ttyio_synth without chec…

published 2021-05-13 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20329

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

A vulnerability was found in Linux Kernel where in the spk_ttyio_receive_buf2() function, it would dereference spk_ttyio_synth without checking whether it is NULL or not, and may lead to a NULL-ptr deref crash.

Patch / fix

  • linux linux_kernel 5.9.14
  • linux Debian 14, Debian 13, Debian 12 5.9.15-1

debian advisories DEBIAN-CVE-2020-27830

  • linux Ubuntu 18.04 LTS 4.15.0-136.140
  • linux Ubuntu 20.04 LTS 5.4.0-66.74
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1094.101
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1038.40
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1093.106~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1037.40
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1036.38
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-136.140~16.04.1

ubuntu advisories UBUNTU-CVE-2020-27830

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-syms SLE Module for Development Tools 15 SP2 5.3.18-24.46.1
  • kernel-source SLE Module for Development Tools 15 SP2, SLE Module for Basesystem 15 SP2 5.3.18-24.46.1
  • kernel-default SLE Workstation Extension 15 SP2, SLE Module for Legacy 15 SP2, SLE Module for Basesystem 15 SP2 +2 more 5.3.18-24.46.1
  • kernel-preempt SLE Module for Development Tools 15 SP2, SLE Module for Basesystem 15 SP2 5.3.18-24.46.1
  • kernel-obs-build SLE Module for Development Tools 15 SP2 5.3.18-24.46.1
  • kernel-default-base SLE Module for Basesystem 15 SP2 5.3.18-24.46.1.9.19.1
  • kernel-rt Real Time Module 15 SP2 5.3.18-22.1
  • kernel-syms-rt Real Time Module 15 SP2 5.3.18-22.1

suse advisories SUSE-SU-2021:0117-1SUSE-SU-2021:0108-1SUSE-SU-2021:0096-1

  • 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 15.2 5.3.18-lp152.60.1
  • kernel-obs-qa openSUSE Leap 15.2 5.3.18-lp152.60.1
  • kernel-source openSUSE Leap 15.2 5.3.18-lp152.60.1
  • kernel-default openSUSE Leap 15.2 5.3.18-lp152.60.1

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

  • linux Arch Linux 5.9.14.arch1-1

arch linux advisories AVG-1330

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-2020-27830 updated cvss 5.5

kernel: null pointer dereference in in spk_ttyio_receive_buf2

  • Red Hat Enterprise Linux 5 kernel 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 MRG 2 kernel
    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

0.30% chance of exploitation in the next 30 days, higher than 23% 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:N/I:N/A:H
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:N/I:N/A:P

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.