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Fencer Vulns
medium 5.5

CVE-2020-36691 json

An issue was discovered in the Linux kernel before 5.8.

published 2023-03-24 3 y ago modified 2026-06-17 4 mo ago also EUVD-2020-24133

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

An issue was discovered in the Linux kernel before 5.8. lib/nlattr.c allows attackers to cause a denial of service (unbounded recursion) via a nested Netlink policy with a back reference.

Patch / fix

  • linux linux_kernel 5.8
  • linux Debian 14, Debian 13, Debian 12 5.8.7-1

debian advisories DEBIAN-CVE-2020-36691

  • linux Ubuntu 20.04 LTS 5.4.0-156.173
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1107.115
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1110.119
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1105.112
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1054.59
  • linux-iot Ubuntu 20.04 LTS 5.4.0-1019.20
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1096.102
  • linux-azure Ubuntu 20.04 LTS 5.4.0-1114.120

ubuntu advisories UBUNTU-CVE-2020-36691

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

  • drbd SLE High Availability Extension 12 SP4 9.0.14+git.62f906cf-4.26.2
  • kernel-syms SLES 12 SP4-LTSS, SLES 12 SP4-ESPOS, OpenStack Cloud Crowbar 9 +1 more 4.12.14-95.125.1
  • kernel-source SLES 12 SP4-LTSS, SLES 12 SP4-ESPOS, OpenStack Cloud Crowbar 9 +1 more 4.12.14-95.125.1
  • kernel-default SLES 12 SP4-LTSS, SLES 12 SP4-ESPOS, SLE Live Patching 12 SP4 +3 more 4.12.14-95.125.1
  • kernel-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.159.1
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.159.1
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.159.1
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.159.1

suse advisories SUSE-SU-2023:2232-1SUSE-SU-2023:2163-1SUSE-SU-2023:2162-1SUSE-SU-2023:2151-1SUSE-SU-2023:2148-1SUSE-SU-2023:2147-1

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-2020-36691 updated cvss 5.9

kernel: lib/nlattr.c allows attackers to cause a denial of service

  • 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, python-perf, kernel-kdump, +8 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, +83 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
20 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.