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01 Record

CVE-2021-3655

A vulnerability was found in the Linux kernel in versions prior to v5.14-rc1. Missing size validations on inbound SCTP packets may allow the kernel to read uninitialized memory.

UnratedPUBLISHEDCNA: redhat
CNA base scoreUnratedNo CNA CVSS vector

02 Description

A vulnerability was found in the Linux kernel in versions prior to v5.14-rc1. Missing size validations on inbound SCTP packets may allow the kernel to read uninitialized memory.

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.30% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 23.3% of scored records. A rank, not a probability.
NVD base score
3.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-10-08.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2021-08-05 20:48Z5 YR AGO
Last updated
2026-10-08 21:03Z20 DAYS AGO
Reserved
2021-07-20
Assigning CNA
redhat
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
  • CWE-909Missing Initialization of ResourceClass
  • CWE-20Improper Input ValidationClass
Data version
5.2
Document digest
ddfdc9b6d1d5962d5f756961bb45e8d2e6c192ddf9f646235a4699529702ed1b

05 Affected products

VendorProductVersionsPlatforms
n/akernelkernel v5.14-rc1—

06 References

07 Fixed in

Arch Linux

  • linux
    Fixed in 5.13.4.arch1-1
  • linux-hardened
    Fixed in 5.12.18.hardened1-1
  • linux-lts
    Fixed in 5.10.51-1
  • linux-zen
    Fixed in 5.13.4.zen1-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

Debian 12

  • linux
    Fixed in 5.10.46-3

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • linux
    Fixed in 5.10.46-3

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • linux
    Fixed in 5.10.46-3

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 16.04 LTS

  • linux-hwe-edge
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • linux
    Fixed in 4.15.0-162.170
  • linux-aws
    Fixed in 4.15.0-1115.122
  • linux-aws-5.0
    No fix yet
  • linux-aws-5.3
    No fix yet
  • linux-aws-5.4
    Fixed in 5.4.0-1060.63~18.04.1
  • linux-azure
    No fix yet
  • linux-azure-4.15
    Fixed in 4.15.0-1126.139
  • linux-azure-5.3
    No fix yet
  • linux-azure-5.4
    Fixed in 5.4.0-1064.67~18.04.1
  • linux-azure-edge
    No fix yet
  • linux-dell300x
    Fixed in 4.15.0-1030.35
  • linux-gcp
    No fix yet
  • linux-gcp-4.15
    Fixed in 4.15.0-1111.125
  • linux-gcp-5.3
    No fix yet
  • linux-gcp-5.4
    Fixed in 5.4.0-1058.62~18.04.1
  • linux-gcp-edge
    No fix yet
  • linux-gke-4.15
    No fix yet
  • linux-gke-5.4
    Fixed in 5.4.0-1056.59~18.04.1
  • linux-gkeop-5.4
    Fixed in 5.4.0-1027.28~18.04.1
  • linux-hwe
    No fix yet
  • linux-hwe-5.4
    Fixed in 5.4.0-91.102~18.04.1
  • linux-hwe-edge
    No fix yet
  • linux-kvm
    Fixed in 4.15.0-1102.104
  • linux-oem
    No fix yet
  • linux-oracle
    Fixed in 4.15.0-1083.91
  • linux-oracle-5.0
    No fix yet
  • linux-oracle-5.3
    No fix yet
  • linux-oracle-5.4
    Fixed in 5.4.0-1058.62~18.04.1
  • linux-raspi-5.4
    Fixed in 5.4.0-1047.52~18.04.1
  • linux-raspi2
    Fixed in 4.15.0-1098.104
  • linux-snapdragon
    Fixed in 4.15.0-1115.124

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • linux
    Fixed in 5.4.0-91.102
  • linux-aws
    Fixed in 5.4.0-1060.63
  • linux-aws-5.11
    Fixed in 5.11.0-1022.23~20.04.1
  • linux-aws-5.8
    No fix yet
  • linux-azure
    Fixed in 5.4.0-1064.67
  • linux-azure-5.11
    Fixed in 5.11.0-1022.23~20.04.1
  • linux-azure-5.8
    No fix yet
  • linux-bluefield
    Fixed in 5.4.0-1022.25
  • linux-gcp
    Fixed in 5.4.0-1058.62
  • linux-gcp-5.11
    Fixed in 5.11.0-1023.25~20.04.1
  • linux-gcp-5.8
    No fix yet
  • linux-gke
    Fixed in 5.4.0-1056.59
  • linux-gkeop
    Fixed in 5.4.0-1027.28
  • linux-hwe-5.11
    Fixed in 5.11.0-41.45~20.04.1
  • linux-hwe-5.13
    Fixed in 5.13.0-22.22~20.04.1
  • linux-hwe-5.8
    No fix yet
  • linux-ibm
    Fixed in 5.4.0-1008.9
  • linux-intel-5.13
    No fix yet
  • linux-kvm
    Fixed in 5.4.0-1050.52
  • linux-oem-5.10
    Fixed in 5.10.0-1051.53
  • linux-oem-5.13
    Fixed in 5.13.0-1020.24
  • linux-oem-5.6
    No fix yet
  • linux-oracle
    Fixed in 5.4.0-1058.62
  • linux-oracle-5.11
    Fixed in 5.11.0-1022.23~20.04.1
  • linux-oracle-5.8
    No fix yet
  • linux-raspi
    Fixed in 5.4.0-1047.52
  • linux-raspi2
    No fix yet
  • linux-riscv
    No fix yet
  • linux-riscv-5.11
    Fixed in 5.11.0-1023.24~20.04.1
  • linux-riscv-5.8
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • linux-intel-iot-realtime
    No fix yet
  • linux-realtime
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 24.04 LTS

  • linux-raspi-realtime
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 14.04 LTS

  • linux
    No fix yet
  • linux-aws
    No fix yet
  • linux-azure
    Fixed in 4.15.0-1126.139~14.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
  • linux-lts-xenial
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 16.04 LTS

  • linux
    No fix yet
  • linux-aws
    No fix yet
  • linux-aws-hwe
    Fixed in 4.15.0-1115.122~16.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
  • linux-azure
    Fixed in 4.15.0-1126.139~16.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
  • linux-gcp
    Fixed in 4.15.0-1111.125~16.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
  • linux-hwe
    Fixed in 4.15.0-162.170~16.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
  • linux-kvm
    No fix yet
  • linux-oracle
    Fixed in 4.15.0-1083.91~16.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 20.04 LTS

  • linux-azure-fde-5.15
    Fixed in 5.15.0-1114.123~20.04.1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS-updates 16.04 LTS

  • linux-fips
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS-updates 18.04 LTS

  • linux-aws-fips
    Fixed in 4.15.0-2056.58
    Available with Ubuntu Pro: https://ubuntu.com/pro
  • linux-azure-fips
    Fixed in 4.15.0-2038.42
    Available with Ubuntu Pro: https://ubuntu.com/pro
  • linux-fips
    Fixed in 4.15.0-1072.81
    Available with Ubuntu Pro: https://ubuntu.com/pro
  • linux-gcp-fips
    Fixed in 4.15.0-2021.23
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS-updates 20.04 LTS

  • linux-aws-fips
    Fixed in 5.4.0-1069.73+fips2
    Available with Ubuntu Pro: https://ubuntu.com/pro
  • linux-azure-fips
    Fixed in 5.4.0-1073.76+fips1
    Available with Ubuntu Pro: https://ubuntu.com/pro
  • linux-fips
    Fixed in 5.4.0-1037.43
    Available with Ubuntu Pro: https://ubuntu.com/pro
  • linux-gcp-fips
    Fixed in 5.4.0-1067.71~20.04.1
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS 16.04 LTS

  • linux-fips
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS 18.04 LTS

  • linux-aws-fips
    No fix yet
  • linux-azure-fips
    No fix yet
  • linux-fips
    No fix yet
  • linux-gcp-fips
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS 20.04 LTS

  • linux-aws-fips
    No fix yet
  • linux-azure-fips
    No fix yet
  • linux-fips
    No fix yet
  • linux-gcp-fips
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.