CVE-2021-20322

Aliases:UBUNTU-CVE-2021-20322DEBIAN-CVE-2021-20322
Advisory lineage Upstream: 0 Downstream: 34
Analyzed
Published: 18 Feb 2022, 17:50
Last modified:30 Jul 2026, 15:52

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.4 HIGH
v3.1 (nvd)
EPSS Score
6.85% LOW
7% probability +6.73%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

18 Feb 2022, 17:50
Published
Vulnerability first disclosed
30 Jul 2026, 15:52
Last Modified
Vulnerability information updated

Description

A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypass the source port UDP randomization. The highest threat from this vulnerability is to confidentiality and possibly integrity, because software that relies on UDP source port randomization are indirectly affected as well.

CVSS Metrics

  • v4.0•CRITICAL•Score: 9.1CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
  • v3.1•HIGH•Score: 7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
  • v2.0•MEDIUM•Score: 5.8AV:N/AC:M/Au:N/C:P/I:P/A:N

EPSS Trends

Current EPSS score: 6.85%• Percentile: 94%

Techniques & Countermeasures

  • CWE-330•Use of Insufficiently Random Values

    The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

Affected Systems

  • debian•linux

    < 5.10.70-1 | < 5.14.6-1 | < 5.14.6-1 | < 5.14.6-1

  • ubuntu•linux

    all | < 4.15.0-167.175 | < 5.4.0-92.103

  • ubuntu•linux-aws

    all | < 4.15.0-1119.127 | < 5.4.0-1061.64

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    < 5.11.0-1021.22~20.04.2

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1061.64~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-fips

    < 4.15.0-2060.62 | all | < 5.4.0-1069.73+fips2

  • ubuntu•linux-aws-hwe

    < 4.15.0-1119.126~16.04.2

  • ubuntu•linux-azure

    < 4.15.0-1130.143~14.04.1 | < 4.15.0-1130.143~16.04.1 | all | < 5.4.0-1065.68

  • ubuntu•linux-azure-4.15

    < 4.15.0-1131.144

  • ubuntu•linux-azure-5.11

    < 5.11.0-1021.22~20.04.1

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1065.68~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde-5.15

    < 5.15.0-1114.123~20.04.1

  • ubuntu•linux-azure-fips

    < 4.15.0-2042.46 | all | < 5.4.0-1073.76+fips1

  • ubuntu•linux-bluefield

    all | < 5.4.0-1023.26

  • ubuntu•linux-dell300x

    < 4.15.0-1034.39

  • ubuntu•linux-fips

    all | < 4.15.0-1076.85 | < 5.4.0-1038.44

  • ubuntu•linux-gcp

    < 4.15.0-1115.129~16.04.1 | all | < 5.4.0-1059.63

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1115.129

  • ubuntu•linux-gcp-5.11

    < 5.11.0-1022.24~20.04.1

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1059.63~18.04.1

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-fips

    < 4.15.0-2025.27 | all | < 5.4.0-1067.71~20.04.1

  • ubuntu•linux-gke

    < 5.4.0-1057.60

  • ubuntu•linux-gke-4.15

    all

  • ubuntu•linux-gke-5.4

    < 5.4.0-1057.60~18.04.1

  • ubuntu•linux-gkeop

    < 5.4.0-1029.30

  • ubuntu•linux-gkeop-5.4

    < 5.4.0-1029.30~18.04.2

  • ubuntu•linux-hwe

    < 4.15.0-167.175~16.04.1 | all

  • ubuntu•linux-hwe-5.11

    all

  • ubuntu•linux-hwe-5.4

    < 5.4.0-92.103~18.04.2

  • ubuntu•linux-hwe-5.8

    all

  • ubuntu•linux-hwe-edge

    all | all

  • ubuntu•linux-ibm

    < 5.4.0-1010.11

  • ubuntu•linux-intel-5.13

    all

  • ubuntu•linux-intel-iot-realtime

    all

  • ubuntu•linux-kvm

    all | < 4.15.0-1106.108 | < 5.4.0-1051.53

  • ubuntu•linux-lts-xenial

    all

  • ubuntu•linux-oem

    all

  • ubuntu•linux-oem-5.10

    < 5.10.0-1050.52

  • ubuntu•linux-oem-5.13

    < 5.13.0-1019.23

  • ubuntu•linux-oem-5.6

    all

  • ubuntu•linux-oracle

    < 4.15.0-1086.94~16.04.1 | < 4.15.0-1086.94 | < 5.4.0-1059.63

  • ubuntu•linux-oracle-5.0

    all

Showing first 50 affected entries in server-rendered view.

References (13)