Is CVE-2021-20177 in the CISA KEV catalog?

No. CVE-2021-20177 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-20177?

CVE-2021-20177 has a CVSS v3 base score of 4.4 (MEDIUM).

What is the EPSS score for CVE-2021-20177?

CVE-2021-20177 has an EPSS score of 0.28% (19th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-20177?

Upgrade linux on debian 11 to 5.5.13-1 or later. Fixes are available for 50 affected products.

CVE & CISA-KEV Catalog

CVE-2021-20177

MEDIUM

4.4

CVSS v3

NVD

Description

A flaw was found in the Linux kernel's implementation of string matching within a packet. A privileged user (with root or CAP_NET_ADMIN) when inserting iptables rules could insert a rule which can panic the system. Kernel before kernel 5.5-rc1 is affected.

CWE-125Out-of-bounds Read

How to fix

Remediation Available

linuxDebian

Fixed in:5.5.13-1CVE-2021-20177

linuxUbuntu

Fixed in:5.4.0-66.74USN-4750-1

linux-awsUbuntu

Fixed in:5.4.0-1038.40USN-4750-1

linux-aws-5.4Ubuntu

Fixed in:5.4.0-1038.40~18.04.1USN-4750-1

linux-azureUbuntu

Fixed in:5.4.0-1040.42USN-4750-1

linux-azure-5.4Ubuntu

Fixed in:5.4.0-1040.42~18.04.1USN-4750-1

linux-gcpUbuntu

Fixed in:5.4.0-1037.40USN-4750-1

linux-gcp-5.4Ubuntu

Fixed in:5.4.0-1037.40~18.04.1USN-4750-1

linux-gke-5.4Ubuntu

Fixed in:5.4.0-1036.38~18.04.1USN-4750-1

linux-gkeopUbuntu

Fixed in:5.4.0-1010.11USN-4750-1

linux-gkeop-5.4Ubuntu

Fixed in:5.4.0-1010.11~18.04.1USN-4750-1

linux-hwe-5.4Ubuntu

Fixed in:5.4.0-66.74~18.04.2USN-4750-1

linux-image-5.4.0-1010-gkeopUbuntu

Fixed in:5.4.0-1010.11~18.04.1USN-4750-1

Fixed in:5.4.0-1010.11USN-4750-1

linux-image-5.4.0-1029-raspiUbuntu

Fixed in:5.4.0-1029.32~18.04.1USN-4750-1

Fixed in:5.4.0-1029.32USN-4750-1

linux-image-5.4.0-1033-kvmUbuntu

Fixed in:5.4.0-1033.34USN-4750-1

linux-image-5.4.0-1036-gkeUbuntu

Fixed in:5.4.0-1036.38~18.04.1USN-4750-1

linux-image-5.4.0-1037-gcpUbuntu

Fixed in:5.4.0-1037.40~18.04.1USN-4750-1

Fixed in:5.4.0-1037.40USN-4750-1

linux-image-5.4.0-1038-awsUbuntu

Fixed in:5.4.0-1038.40~18.04.1USN-4750-1

Fixed in:5.4.0-1038.40USN-4750-1

linux-image-5.4.0-1038-oracleUbuntu

Fixed in:5.4.0-1038.41~18.04.1USN-4750-1

Fixed in:5.4.0-1038.41USN-4750-1

linux-image-5.4.0-1040-azureUbuntu

Fixed in:5.4.0-1040.42~18.04.1USN-4750-1

Fixed in:5.4.0-1040.42USN-4750-1

linux-image-5.4.0-66-genericUbuntu

Fixed in:5.4.0-66.74~18.04.2USN-4750-1

Fixed in:5.4.0-66.74USN-4750-1

linux-image-5.4.0-66-generic-lpaeUbuntu

Fixed in:5.4.0-66.74~18.04.2USN-4750-1

Fixed in:5.4.0-66.74USN-4750-1

linux-image-5.4.0-66-lowlatencyUbuntu

Fixed in:5.4.0-66.74~18.04.2USN-4750-1

Fixed in:5.4.0-66.74USN-4750-1

linux-image-awsUbuntu

Fixed in:5.4.0.1038.22USN-4750-1

Fixed in:5.4.0.1038.39USN-4750-1

linux-image-azureUbuntu

Fixed in:5.4.0.1040.20USN-4750-1

Fixed in:5.4.0.1040.38USN-4750-1

linux-image-gcpUbuntu

Fixed in:5.4.0.1037.24USN-4750-1

Fixed in:5.4.0.1037.46USN-4750-1

linux-image-genericUbuntu

Fixed in:5.4.0.66.69USN-4750-1

linux-image-generic-hwe-18.04Ubuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

linux-image-generic-lpaeUbuntu

Fixed in:5.4.0.66.69USN-4750-1

linux-image-generic-lpae-hwe-18.04Ubuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

linux-image-gke-5.4Ubuntu

Fixed in:5.4.0.1036.38~18.04.4USN-4750-1

linux-image-gkeopUbuntu

Fixed in:5.4.0.1010.13USN-4750-1

linux-image-gkeop-5.4Ubuntu

Fixed in:5.4.0.1010.11~18.04.11USN-4750-1

Fixed in:5.4.0.1010.13USN-4750-1

linux-image-kvmUbuntu

Fixed in:5.4.0.1033.31USN-4750-1

linux-image-lowlatencyUbuntu

Fixed in:5.4.0.66.69USN-4750-1

linux-image-lowlatency-hwe-18.04Ubuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

linux-image-oemUbuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

Fixed in:5.4.0.66.69USN-4750-1

linux-image-oem-osp1Ubuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

Fixed in:5.4.0.66.69USN-4750-1

linux-image-oracleUbuntu

Fixed in:5.4.0.1038.41~18.04.21USN-4750-1

Fixed in:5.4.0.1038.35USN-4750-1

linux-image-raspiUbuntu

Fixed in:5.4.0.1029.64USN-4750-1

linux-image-raspi-hwe-18.04Ubuntu

Fixed in:5.4.0.1029.32USN-4750-1

linux-image-raspi2Ubuntu

Fixed in:5.4.0.1029.64USN-4750-1

linux-image-snapdragon-hwe-18.04Ubuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

linux-image-virtualUbuntu

Fixed in:5.4.0.66.69USN-4750-1

linux-image-virtual-hwe-18.04Ubuntu

Fixed in:5.4.0.66.74~18.04.61USN-4750-1

linux-kvmUbuntu

Fixed in:5.4.0-1033.34USN-4750-1

linux-oracleUbuntu

Fixed in:5.4.0-1038.41USN-4750-1

linux-oracle-5.4Ubuntu

Fixed in:5.4.0-1038.41~18.04.1USN-4750-1

linux-raspiUbuntu

Fixed in:5.4.0-1029.32USN-4750-1

linux-raspi-5.4Ubuntu

Fixed in:5.4.0-1029.32~18.04.1USN-4750-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.28%probability of exploitation in 30 days

19thpercentile

Low risk: more likely to be exploited than 19% of all known CVEs.

References

Patch1

bugzilla.redhat.com

Related Vulnerabilities

Other CWE-125 (Out-of-bounds Read) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0160	High	7.5	100%	KEV	Fix
CVE-2025-5777	High	7.5	100%	KEV + Ransom	Fix
CVE-2021-4034	High	7.8	95%	KEV	Fix
CVE-2023-21769	High	7.5	92%	-	Fix
CVE-2023-49285	High	8.6	89%	-	Fix
CVE-2020-8794	Critical	9.8	89%	-	Fix

Embed a live status badge for CVE-2021-20177

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.