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Fencer Vulns
medium 6.0

CVE-2020-27171 json

An issue was discovered in the Linux kernel before 5.11.8.

published 2021-03-20 5 y ago modified 2026-10-08 31 d ago also EUVD-2020-19695

cvss
6.0
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c has an off-by-one error (with a resultant integer underflow) affecting out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory, aka CID-10d2bb2e6b1d.

Patch / fix

  • linux linux_kernel 5.11.8
  • linux Debian 14, Debian 13, Debian 12 5.10.24-1

debian advisories DEBIAN-CVE-2020-27171

  • linux Ubuntu 18.04 LTS 4.15.0-140.144
  • linux Ubuntu 20.04 LTS 5.4.0-70.78
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1097.104
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1041.43
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1096.109~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1040.43
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1039.41
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-140.144~16.04.1

ubuntu advisories UBUNTU-CVE-2020-27171

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 5.10.78.1-1

azure linux advisories AZL-6526

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 5.11.8.arch1-1
  • linux-hardened Arch Linux 5.11.8.hardened1-1
  • linux-zen Arch Linux 5.11.8.zen1-1
  • linux-lts Arch Linux 5.10.25-1

arch linux advisories AVG-1711AVG-1712AVG-1713AVG-1714

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-2020-27171 updated cvss 6.0

kernel: Integer underflow when restricting speculative pointer arithmetic

  • Red Hat Enterprise Linux 7 kernel, bpftool, kernel-rt, kernel-rt-kvm, kernel-rt-trace, kernel-rt-debug-kvm, +1 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, kernel-alt, python-perf, kernel-kdump, kernel-tools, +3 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
31 d ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.0 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 3.6 AV:L/AC:L/Au:N/C:P/I:N/A:P

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.