What’s Vulnerable › Vulnerabilities

CVE-2021-3690

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-08-23 · updated 2026-06-17
• Weakness: CWE-400

Description

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.

Affected products

• Red Hat Fuse: 1.0
• RedHat Integration Camel K: all versions
• RedHat Integration Camel Quarkus: all versions
• 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 2.0.40; from 2.1.0 before 2.2.10 — fixed in 2.0.40, 2.2.10

How to fix

Upgrade to a fixed version: Red Hat undertow 2.0.40, 2.2.10. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/security/cve/CVE-2021-3690
• https://bugzilla.redhat.com/show_bug.cgi?id=1991299
• https://github.com/undertow-io/undertow/commit/c7e84a0b7efced38506d7d1dfea5902366973877
• https://issues.redhat.com/browse/UNDERTOW-1935
• https://access.redhat.com/security/cve/CVE-2021-3690
• https://bugzilla.redhat.com/show_bug.cgi?id=1991299
• https://github.com/undertow-io/undertow/commit/c7e84a0b7efced38506d7d1dfea5902366973877
• https://issues.redhat.com/browse/UNDERTOW-1935

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