CVE-2021-3597

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-05-24 · updated 2026-06-17
Weakness: CWE-362

Description

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.

Affected products

Active IQ Unified Manager for VMware vSphere, Linux, and Microsoft Windows: all versions
OnCommand Insight: all versions
NetApp OnCommand Workflow Automation: all versions
Red Hat Fuse: 1.0
Red Hat JBoss EAP: 7.3, 7.4
RedHat Openshift Application Runtimes: all versions
Red Hat Single Sign-On: all versions
Red Hat undertow: before 2.0.35; from 2.2.0 before 2.2.6; 2.0.35, 2.0.36, 2.0.39, 2.2.6, 2.2.7, 2.2.9 — fixed in 2.0.35, 2.2.6

How to fix

Upgrade to a fixed version: Red Hat undertow 2.0.35, 2.2.6. Check the vendor advisory for mitigations.

References

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