Is CVE-2021-20220 in the CISA KEV catalog?

No. CVE-2021-20220 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-20220?

CVE-2021-20220 has a CVSS v3 base score of 4.8 (MEDIUM).

What is the EPSS score for CVE-2021-20220?

CVE-2021-20220 has an EPSS score of 1.12% (62th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-20220?

Upgrade undertow on debian unstable to 2.2.0-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-20220

MEDIUM

4.8

CVSS v3

NVD

Description

A flaw was found in Undertow. A regression in the fix for CVE-2020-10687 was found. HTTP request smuggling related to CVE-2017-2666 is possible against HTTP/1.x and HTTP/2 due to permitting invalid characters in an HTTP request. This flaw allows an attacker to poison a web-cache, perform an XSS attack, or obtain sensitive information from request other than their own. The highest threat from this vulnerability is to data confidentiality and integrity.

CWE-444

How to fix

Remediation Available

undertowDebian

Fixed in:2.2.0-1CVE-2021-20220

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 VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

1.12%probability of exploitation in 30 days

62ndpercentile

Moderate risk: more likely to be exploited than 62% of all known CVEs.

References

Vendor Advisory1

bugzilla.redhat.com

Third-Party Advisory1

security.netapp.com

Related Vulnerabilities

Other CWE-444 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-22536	Critical	10.0	98%	KEV	-
CVE-2025-61884	High	7.5	98%	KEV + Ransom	-
CVE-2020-9490	High	7.5	90%	-	Fix
CVE-2023-41265	Critical	9.6	85%	KEV + Ransom	-
CVE-2023-25690	Critical	9.8	84%	-	Fix
CVE-2022-32214	Medium	6.5	78%	-	Fix

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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.