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CVE-2021-3597· NVD / CVE Program· CNA redhat

A flaw was found in undertow.

Noroxi assessment

Priority: Monitor (action score 23/100)

  • 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: 1.1% (FIRST EPSS); higher than 66.9% 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. Special conditions such as timing or configuration are required.
  • Fixed version: undertow (Debian:14) 2.2.10-1; io.undertow:undertow-core (Maven) 2.2.9.Final, 2.0.39.Final; eap7-apache-commons-io (Red Hat:jboss_enterprise_application_platform:7.3::el6) 0:2.10.0-1.redhat_00001.1.el6eap.
  • Mentioned 1 time 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) 2.2.9.Final, 2.0.39.Final; eap7-apache-commons-io (Red Hat:jboss_enterprise_application_platform:7.3::el6) 0:2.10.0-1.redhat_00001.1.el6eap 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. The HTTP2SourceChannel fails to write the final frame under some circumstances, resulting in a denial of service. The highest threat from this vulnerability is availability. This flaw affects Undertow versions prior to 2.0.35.SP1, prior to 2.2.6.SP1, prior to 2.2.7.SP1, prior to 2.0.36.SP1, prior to 2.2.9.Final and prior to 2.0.39.Final.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
May 24, 2022
Updated
Jun 17, 2026
EPSS
1.1% · 66th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-3597

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
redhatfuse
redhatjboss enterprise application platform
redhatopenshift application runtimes
redhatsingle sign-on
redhatundertow
redhatenterprise linux
netappactive iq unified manager
netapponcommand insight
netapponcommand workflow automation

Affected versions

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

  • netapp active iq unified managerall versions
  • netapp oncommand insightall versions
  • netapp oncommand workflow automationall versions
  • redhat fuse1.0
  • 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 2.0.35
  • redhat undertow2.2.0 and later · before 2.2.6
  • redhat undertow2.0.35
  • redhat undertow2.0.36
  • redhat undertow2.0.39
  • redhat undertow2.2.6
  • redhat undertow2.2.7
  • redhat undertow2.2.9

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

    • undertow 2.0.35.SP1, undertow 2.2.6.SP1, undertow 2.2.7.SP1, undertow 2.0.36.SP1, undertow 2.2.9.Final, undertow 2.0.39.Finalaffected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:14undertowbefore 2.2.10-12.2.10-1
Mavenio.undertow:undertow-corefrom 2.1.0 · before 2.2.9.Final2.2.9.Final
Mavenio.undertow:undertow-corebefore 2.0.39.Final2.0.39.Final
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-apache-commons-iobefore 0:2.10.0-1.redhat_00001.1.el6eap0:2.10.0-1.redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-hal-consolebefore 0:3.2.16-1.Final_redhat_00001.1.el6eap0:3.2.16-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-hibernatebefore 0:5.3.20-4.SP2_redhat_00001.1.el6eap0:5.3.20-4.SP2_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-hibernate-corebefore 0:5.3.20-4.SP2_redhat_00001.1.el6eap0:5.3.20-4.SP2_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-hibernate-entitymanagerbefore 0:5.3.20-4.SP2_redhat_00001.1.el6eap0:5.3.20-4.SP2_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-hibernate-enversbefore 0:5.3.20-4.SP2_redhat_00001.1.el6eap0:5.3.20-4.SP2_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-hibernate-java8before 0:5.3.20-4.SP2_redhat_00001.1.el6eap0:5.3.20-4.SP2_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamarbefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-common-apibefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-common-implbefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-common-spibefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-core-apibefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-core-implbefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-deployers-commonbefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-jdbcbefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-ironjacamar-validatorbefore 0:1.4.35-1.Final_redhat_00001.1.el6eap0:1.4.35-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-jakarta-elbefore 0:3.0.3-2.redhat_00006.1.el6eap0:3.0.3-2.redhat_00006.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-jberetbefore 0:1.3.9-1.Final_redhat_00001.1.el6eap0:1.3.9-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-jberet-corebefore 0:1.3.9-1.Final_redhat_00001.1.el6eap0:1.3.9-1.Final_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-jboss-remotingbefore 0:5.0.23-2.SP1_redhat_00001.1.el6eap0:5.0.23-2.SP1_redhat_00001.1.el6eap
Red Hat:jboss_enterprise_application_platform:7.3::el6eap7-jboss-server-migrationbefore 0:1.7.2-9.Final_redhat_00010.1.el6eap0:1.7.2-9.Final_redhat_00010.1.el6eap

+96

Same product

redhat: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-3690A flaw was found in Undertow.
    31Monitor
  • 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

Published before and after this one in the same product

  • ← EarlierCVE-2020-10688May 27, 2021 · A 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

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
debian:undertow2.2.10-1 · Debian:14Package registry (OSV)
Maven:io.undertow:undertow-core2.0.39.FinalPackage registry (OSV)
Maven:io.undertow:undertow-core2.2.9.FinalPackage registry (OSV)
red hat:eap7-apache-commons-io0:2.10.0-1.redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-hal-console0:3.2.16-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-hibernate0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-hibernate-core0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-hibernate-entitymanager0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-hibernate-envers0:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-hibernate-java80:5.3.20-4.SP2_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-ironjacamar0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-ironjacamar-common-api0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-ironjacamar-common-impl0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-ironjacamar-common-spi0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package registry (OSV)
red hat:eap7-ironjacamar-core-api0:1.4.35-1.Final_redhat_00001.1.el6eap · Red Hat:jboss_enterprise_application_platform:7.3::el6Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

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

No commit or PR link among the references.

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.

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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (1 more)

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

All records