CVE-2026-14180: Undertow-core: undertow:http request smuggling via oversized chunk-size bit overlap

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-11 · updated 2026-10-20
Weakness: CWE-444

Description

A flaw was found in the ChunkReader component of the Undertow HTTP server, which is used by WildFly and JBoss EAP to handle chunked transfer encoding. The issue occurs because the parser uses a single internal variable to store both the remaining chunk size and state flags. By sending a specially crafted request with an extremely large chunk size, an attacker can cause these values to overlap, tricking the parser into thinking a request has finished prematurely. This can allow a second, "smuggled" request to be processed out of sync, potentially bypassing security controls.

Affected products

Red Hat build of Apache Camel - HawtIO 4: all versions
Red Hat build of Apache Camel for Spring Boot 4: all versions
Red Hat Data Grid 8: all versions
Red Hat Enterprise Linux 10: all versions
Red Hat Enterprise Linux 8: all versions
Red Hat Enterprise Linux 9: all versions
Red Hat Fuse 7: all versions
Red Hat JBoss Enterprise Application Platform 7: all versions
Red Hat JBoss Enterprise Application Platform 8.1.8.GA: all versions — fixed in 2.3.26.SP3-redhat-00001
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 10: all versions — fixed in 0:1.1.9-1.redhat_00001.1.el10eap, 0:1.2.7-1.redhat_00002.1.el10eap, 0:1.85.0-1.redhat_00001.1.el10eap, 0:2.0.18-1.redhat_00001.1.el10eap, 0:2.0.5-1.Final_redhat_00001.1.el10eap, 0:2.1.0-1.redhat_00001.1.el10eap
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8: all versions — fixed in 0:1.1.9-1.redhat_00001.1.el8eap, 0:1.2.7-1.redhat_00002.1.el8eap, 0:1.85.0-1.redhat_00001.1.el8eap, 0:2.0.18-1.redhat_00001.1.el8eap, 0:2.0.5-1.Final_redhat_00001.1.el8eap, 0:2.1.0-1.redhat_00001.1.el8eap
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9: all versions — fixed in 0:1.1.9-1.redhat_00001.1.el9eap, 0:1.2.7-1.redhat_00002.1.el9eap, 0:1.85.0-1.redhat_00001.1.el9eap, 0:2.0.18-1.redhat_00001.1.el9eap, 0:2.0.5-1.Final_redhat_00001.1.el9eap, 0:2.1.0-1.redhat_00001.1.el9eap
Red Hat JBoss Enterprise Application Platform Expansion Pack: all versions
Red Hat Single Sign-On 7: all versions

How to fix

Upgrade to a fixed version: Red Hat JBoss Enterprise Application Platform 8.1.8.GA 2.3.26.SP3-redhat-00001; Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 10 0:1.1.9-1.redhat_00001.1.el10eap, 0:1.2.7-1.redhat_00002.1.el10eap, 0:1.85.0-1.redhat_00001.1.el10eap, 0:2.0.18-1.redhat_00001.1.el10eap; Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 0:1.1.9-1.redhat_00001.1.el8eap, 0:1.2.7-1.redhat_00002.1.el8eap, 0:1.85.0-1.redhat_00001.1.el8eap, 0:2.0.18-1.redhat_00001.1.el8eap; Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 0:1.1.9-1.redhat_00001.1.el9eap, 0:1.2.7-1.redhat_00002.1.el9eap, 0:1.85.0-1.redhat_00001.1.el9eap, 0:2.0.18-1.redhat_00001.1.el9eap. Check the vendor advisory for mitigations.

References

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