NVD / CVE Program· CNA redhat

CVE-2021-3690: A flaw was found in Undertow.

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 1.7% (FIRST EPSS); higher than 78.1% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: undertow (Debian:14) 2.2.10-1; io.undertow:undertow-core (Maven) 2.2.10, 2.0.40; eap7-activemq-artemis (Red Hat:jboss_enterprise_application_platform_eus:7.1::el7) 0:1.5.5.016-1.redhat_00001.1.ep7.el7.
Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to undertow (Debian:14) 2.2.10-1; io.undertow:undertow-core (Maven) 2.2.10, 2.0.40; eap7-activemq-artemis (Red Hat:jboss_enterprise_application_platform_eus:7.1::el7) 0:1.5.5.016-1.redhat_00001.1.ep7.el7 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A flaw was found in Undertow. A buffer leak on the incoming WebSocket PONG message may lead to memory exhaustion. This flaw allows an attacker to cause a denial of service. The highest threat from this vulnerability is availability.

HighCVSS 7.5 · v3.1—No exploit Fix available

Published: Aug 23, 2022
Updated: Jun 17, 2026
EPSS: 1.7% · 78th percentile
CWE: CWE-400

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 1 / 30 · 1.7%

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
redhat	single sign-on	cpe:2.3:a:redhat:single_sign-on
redhat	undertow	cpe:2.3:a:redhat:undertow
redhat	fuse	cpe:2.3:a:redhat:fuse
redhat	integration camel k	cpe:2.3:a:redhat:integration_camel_k
redhat	integration camel quarkus	cpe:2.3:a:redhat:integration_camel_quarkus
redhat	jboss enterprise application platform	cpe:2.3:a:redhat:jboss_enterprise_application_platform
redhat	openshift application runtimes	cpe:2.3:a:redhat:openshift_application_runtimes
redhat	enterprise linux	cpe:2.3:o:redhat:enterprise_linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

redhat fuse1.0
redhat integration camel kall versions
redhat integration camel quarkusall versions
redhat jboss enterprise application platformall versions
redhat jboss enterprise application platform7.3
redhat jboss enterprise application platform7.4
redhat openshift application runtimesall versions
redhat single sign-onall versions
redhat undertowbefore 2.0.40
redhat undertow2.1.0 and later · before 2.2.10

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

n/a undertow
- Fixed in 2.2.10.Final, 2.0.40.Finalaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

+96

Same product

redhat: all records

Other highest-scoring records for the same primary product.

CVE-2019-14860It was found that the Syndesis configuration for Cross-Origin Resource Sharing was set to allow all origins.
26Monitor
CVE-2025-57849Fuse: privilege escalation via excessive /etc/passwd permissions
25Monitor
CVE-2020-10688A cross-site scripting (XSS) flaw was found in RESTEasy in versions before 3.11.1.Final and before 4.5.3.Final, where it did not properly ha
24Monitor

Published before and after this one in the same product

← EarlierCVE-2021-3597May 24, 2022 · A flaw was found in undertow.
23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
debian:undertow	2.2.10-1 · Debian:14	Package registry (OSV)
Maven:io.undertow:undertow-core	2.0.40	Package registry (OSV)
Maven:io.undertow:undertow-core	2.2.10	Package registry (OSV)
red hat:eap7-apache-commons-io	0:2.10.0-1.redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-hal-console	0:3.2.16-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-hibernate	0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-hibernate-core	0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-hibernate-entitymanager	0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-hibernate-envers	0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-hibernate-java8	0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-ironjacamar	0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-ironjacamar-common-api	0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-ironjacamar-common-impl	0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-ironjacamar-common-spi	0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)
red hat:eap7-undertow	0:2.0.38-2.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

undertow-io/undertowcommit c7e84a0

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-22-0247 · Mar 24, 2022(RedHat Güvenlik Güncellemesi)
TR-21-0737 · Sep 15, 2021(RedHat Güvenlik Güncellemesi)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

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

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

Fix✗ → ✓Sep 28, 2026, 10:46 PM UTC

For records you follow, these changes also arrive as notifications. →

References

access.redhat.com/security/cve/CVE-2021-3690

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records

Ecosystem	Package	Affected range	Fix
Debian:14	undertow	before 2.2.10-1	2.2.10-1
Maven	io.undertow:undertow-core	from 2.2.0 · before 2.2.10	2.2.10
Maven	io.undertow:undertow-core	before 2.0.40	2.0.40
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-cli	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-commons	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-core-client	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-dto	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-hornetq-protocol	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-hqclient-protocol	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-jdbc-store	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-jms-client	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-jms-server	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-journal	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-native	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-ra	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-selector	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-server	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-activemq-artemis-service-extensions	before 0:1.5.5.016-1.redhat_00001.1.ep7.el7	0:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-artemis-native	before 1:1.5.5.016-1.redhat_00001.1.ep7.el7	1:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-artemis-native-debuginfo	before 1:1.5.5.016-1.redhat_00001.1.ep7.el7	1:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-artemis-native-wildfly	before 1:1.5.5.016-1.redhat_00001.1.ep7.el7	1:1.5.5.016-1.redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-jboss-xnio-base	before 0:3.5.11-1.Final_redhat_00001.1.ep7.el7	0:3.5.11-1.Final_redhat_00001.1.ep7.el7
Red Hat:jboss_enterprise_application_platform_eus:7.1::el7	eap7-jsoup	before 0:1.14.2-1.redhat_00002.1.ep7.el7	0:1.14.2-1.redhat_00002.1.ep7.el7