HOMEVULNERABILITIESCVE-2021-20220
MEDIUM

CVE-2021-20220

CWE-444Published: February 23, 2021· Updated: Jun 17, 2026

4.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-20220 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.None
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

Affected Vendors & Products

netapp2 product(s)
active iq unified manageroncommand workflow automation
Red Hat1 product(s)
undertow
Source: NVD CPE · 3 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://bugzilla.redhat.com/show_bug.cgi?id=1923133
ADVISORYhttps://security.netapp.com/advisory/ntap-20220210-0013/
ADVISORYhttps://bugzilla.redhat.com/show_bug.cgi?id=1923133
ADVISORYhttps://security.netapp.com/advisory/ntap-20220210-0013/

All References (4)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1923133Issue Tracking · Vendor Advisory
→
https://security.netapp.com/advisory/ntap-20220210-0013/Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1923133Issue Tracking · Vendor Advisory
→
https://security.netapp.com/advisory/ntap-20220210-0013/Third Party Advisory

Quick Facts

CVE IDCVE-2021-20220
CVSS Score4.8 / 10
SeverityMEDIUM
WeaknessCWE-444
CISA KEVNo
Affected2 vendor(s)
PublishedFeb 23, 2021

Related CVEs (CWE-444)

CVE-2018-3907
10.0
CVE-2025-1867
10.0
CVE-2025-55315
9.9
CVE-2017-7657
9.8
CVE-2022-24766
9.8
CVE-2021-39214
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-20220 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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