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Fencer Vulns
high 7.8

CVE-2020-27815 json

A flaw was found in the JFS filesystem code in the Linux Kernel which allows a local attacker with the ability to set extended attributes t…

published 2021-05-26 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20316

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits
0
none known

Summary

A flaw was found in the JFS filesystem code in the Linux Kernel which allows a local attacker with the ability to set extended attributes to panic the system, causing memory corruption or escalating privileges. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Patch / fix

  • linux linux_kernel 4.9.249, 4.14.213, 4.19.164, 5.4.86, 5.10.4
  • linux Debian 14, Debian 13, Debian 12 5.10.4-1

debian advisories DEBIAN-CVE-2020-27815

  • linux Ubuntu 16.04 LTS 4.4.0-203.235
  • linux Ubuntu 18.04 LTS 4.15.0-136.140
  • linux Ubuntu 20.04 LTS 5.4.0-66.74
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1122.136
  • 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

ubuntu advisories UBUNTU-CVE-2020-27815

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-64kb SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-syms SLE Module for Development Tools 15 SP3 5.3.18-59.5.1
  • kernel-source SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-default SLE Workstation Extension 15 SP3, SLE Module for Legacy 15 SP3, SLE Module for Basesystem 15 SP3 +2 more 5.3.18-59.5.2
  • kernel-preempt SLE Workstation Extension 15 SP3, SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-zfcpdump SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-obs-build SLE Module for Development Tools 15 SP3 5.3.18-59.5.1
  • kernel-default-base SLE Module for Basesystem 15 SP3 5.3.18-59.5.2.18.2.2

suse advisories SUSE-SU-2021:1977-1SUSE-SU-2021:1975-1SUSE-SU-2021:1625-1SUSE-SU-2021:1624-1SUSE-SU-2021:1596-1SUSE-SU-2021:1573-1

  • kernel-64kb openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-syms openSUSE Leap 15.3 5.3.18-59.5.1
  • kernel-obs-qa openSUSE Leap 15.3 5.3.18-59.5.1
  • kernel-source openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-default openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-preempt openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-kvmsmall openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-zfcpdump openSUSE Leap 15.3 5.3.18-59.5.2

opensuse advisories openSUSE-SU-2021:1977-1openSUSE-SU-2021:1975-1openSUSE-SU-2021:0758-1openSUSE-SU-2021:0532-1

  • kernel CBL-Mariner 2.0 5.15.135.1-2
  • kernel Azure Linux 3.0 6.6.29.1-4

azure linux advisories AZL-31148AZL-34856

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • linux Arch Linux 5.10.4.arch1-1

arch linux advisories AVG-1394

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-2020-27815 updated cvss 7.4

kernel: Array index out of bounds access when setting extended attributes on journaling filesystems.

  • Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • 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 Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    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

0.79% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2020/12/28/1 referenced PoC, tagged "exploit" by a source, unverified
  • openwall.com http://www.openwall.com/lists/oss-security/2020/11/30/5 referenced PoC, tagged "exploit" by a source, unverified

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 6.1 AV:L/AC:L/Au:N/C:P/I:P/A:C

Affected products

  • n/a Linux Kernel

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-787 Out-of-bounds Write
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.