CVE-2021-22555

Aliases:RHSA-2025:17733UBUNTU-CVE-2021-22555DEBIAN-CVE-2021-22555
Advisory lineage Upstream: 0 Downstream: 52
Analyzed
Published: 07 Jul 2021, 11:20
Last modified:30 Dec 2025, 20:32

Vulnerability Summary

Overall Risk (default)
high
59/100
CVSS Score
8.3 HIGH
v3.1 (cve.org)
EPSS Score
78.68% CRITICAL
79% probability -6.55%
KEV
Listed
CISA
1 listing
Ransomware
No reports
Public exploits
7 found
Dark Web
Not detected

Timeline

07 Jul 2021, 11:20
Published
Vulnerability first disclosed
06 Oct 2025, 00:00
Added to CISA KEV
Linux Kernel Heap Out-of-Bounds Write Vulnerability
27 Oct 2025, 00:00
CISA Remediation Due
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
30 Dec 2025, 20:32
Last Modified
Vulnerability information updated

Description

A heap out-of-bounds write affecting Linux since v2.6.19-rc1 was discovered in net/netfilter/x_tables.c. This allows an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space

CVSS Metrics

  • v3.1•HIGH•Score: 8.3CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • v2.0•MEDIUM•Score: 4.6AV:L/AC:L/Au:N/C:P/I:P/A:P

EPSS Trends

Current EPSS score: 78.68%• Percentile: 100%

Techniques & Countermeasures

  • CWE-787•Out-of-bounds Write

    The product writes data past the end, or before the beginning, of the intended buffer.

Affected Systems

  • brocade•fabric_operating_system

    na

  • debian•linux

    < 5.10.38-1 | < 5.10.38-1 | < 5.10.38-1 | < 5.10.38-1

  • ubuntu•linux

    < 3.13.0-187.238 | < 4.4.0-213.245 | < 4.15.0-144.148 | < 5.4.0-74.83

  • ubuntu•linux-aws

    < 4.4.0-1095.100 | < 4.4.0-1131.145 | < 4.15.0-1103.110 | < 5.4.0-1049.51

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1049.51~18.04.1

  • ubuntu•linux-aws-fips

    < 4.15.0-2045.47 | all | < 5.4.0-1069.73+fips2

  • ubuntu•linux-aws-hwe

    < 4.15.0-1103.110~16.04.1

  • ubuntu•linux-azure

    < 4.15.0-1115.128~14.04.1 | < 4.15.0-1115.128~16.04.1 | all | < 5.4.0-1048.50

  • ubuntu•linux-azure-4.15

    < 4.15.0-1115.128

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1048.50~18.04.1

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fips

    < 4.15.0-2027.30 | all | < 5.4.0-1073.76+fips1

  • ubuntu•linux-bluefield

    all | < 5.4.0-1012.15

  • ubuntu•linux-dell300x

    < 4.15.0-1022.26

  • ubuntu•linux-fips

    < 4.4.0-1065.71 | all | < 4.15.0-1060.68

  • ubuntu•linux-gcp

    < 4.15.0-1100.113~16.04.1 | all | < 5.4.0-1044.47

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1100.113

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1044.47~18.04.2

  • ubuntu•linux-gcp-edge

    all

  • ubuntu•linux-gcp-fips

    all | < 5.4.0-1067.71~20.04.1

  • ubuntu•linux-gke

    < 5.4.0-1044.46

  • ubuntu•linux-gke-4.15

    all

  • ubuntu•linux-gke-5.4

    < 5.4.0-1044.46~18.04.1

  • ubuntu•linux-gkeop

    < 5.4.0-1016.17

  • ubuntu•linux-gkeop-5.4

    < 5.4.0-1016.17~18.04.1

  • ubuntu•linux-hwe

    < 4.15.0-144.148~16.04.1 | all

  • ubuntu•linux-hwe-5.4

    < 5.4.0-74.83~18.04.1

  • ubuntu•linux-hwe-5.8

    < 5.8.0-55.62~20.04.1

  • ubuntu•linux-hwe-edge

    all | all

  • ubuntu•linux-intel-iot-realtime

    all

  • ubuntu•linux-kvm

    < 4.4.0-1096.105 | < 4.15.0-1092.94 | < 5.4.0-1040.41

  • ubuntu•linux-lts-xenial

    < 4.4.0-213.245~14.04.1

  • ubuntu•linux-oem

    all

  • ubuntu•linux-oem-5.10

    < 5.10.0-1025.26

  • ubuntu•linux-oem-5.6

    all

  • ubuntu•linux-oracle

    < 4.15.0-1072.80~16.04.1 | < 4.15.0-1072.80 | < 5.4.0-1046.50

  • ubuntu•linux-oracle-5.0

    all

  • ubuntu•linux-oracle-5.3

    all

  • ubuntu•linux-oracle-5.4

    < 5.4.0-1046.50~18.04.2

  • ubuntu•linux-raspi

    < 5.4.0-1036.39

  • ubuntu•linux-raspi-5.4

    < 5.4.0-1036.39~18.04.1

  • ubuntu•linux-raspi-realtime

    all

  • ubuntu•linux-raspi2

    < 4.15.0-1086.91 | all

  • ubuntu•linux-realtime

    all

  • ubuntu•linux-riscv

    all

  • ubuntu•linux-riscv-5.8

    < 5.8.0-26.28~20.04.1

Showing first 50 affected entries in server-rendered view.

References (21)