CVE-2026-78329: Apache Camel Undertow header filter bypass in endpoint routes

CVE-2026-78329 · Severity: critical · CVSS 9.8 · Published 2026-08-24

Apache Camel's Undertow component is used to integrate web services and messaging in enterprise applications. A configuration bug caused the endpoint to ignore the Undertow-specific header filtering rules, allowing attackers to inject malicious headers that could redirect WebSocket connections to unintended recipients or bypass security policies. This affects applications using Camel to route messages through Undertow endpoints without explicit header filtering configuration.

Technologies: Apache Camel, org.apache.camel:camel-undertow (Maven). Vendors: Apache, Maven.

Quick answers

Is CVE-2026-78329 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-78329 being exploited in the wild.
How severe is CVE-2026-78329?
Critical severity, with a CVSS score of 9.8, published 24 August 2026.
Which products and versions are affected?
Apache Camel 4.11.0 to 4.14.8, 4.15.0 to 4.18.3, 4.19.0 to 4.21.x; org.apache.camel:camel-undertow (Maven) ECOSYSTEM:introduced=4.11.0,fixed=4.14.9.
Is there a fix for CVE-2026-78329?
Yes. org.apache.camel:camel-undertow (Maven): upgrade to 4.14.9 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-78329 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-78329?
Check whether you run Apache Camel or org.apache.camel:camel-undertow (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • org.apache.camel:camel-undertow (Maven): upgrade to 4.14.9 or later
    # set org.apache.camel:camel-undertow to 4.14.9 in your pom.xml or build.gradle

Technical details

The vulnerability is an improper input validation issue (CWE-20) in the UndertowEndpoint class. The root cause: UndertowEndpoint defaults its headerFilterStrategy field to the base HttpHeaderFilterStrategy and immediately overwrites the UndertowHeaderFilterStrategy that should be applied by DefaultUndertowHttpBinding, preventing Undertow-specific header filtering from executing on endpoint-configured routes. An unauthenticated remote attacker can send HTTP requests with crafted headers (specifically the legacy "websocket." prefixed headers) that are not filtered at the transport boundary. An undertow HTTP consumer maps these unfiltered inbound headers onto the Exchange message, where an undertow WebSocket producer reads them as dispatch directives, allowing the attacker to redirect WebSocket messages to peers other than those selected by the route. Additionally, header names that Undertow itself rejects are mapped onto the Exchange rather than being skipped, enabling header injection attacks. No authentication is required; the attack is exploitable over the network with low complexity. Patches are available in versions 4.14.9, 4.18.4, and 4.22.0. Rest DSL consumers are not affected because they explicitly assign UndertowRestHeaderFilterStrategy.

Affected products

  • Apache Camel 4.11.0 to 4.14.8, 4.15.0 to 4.18.3, 4.19.0 to 4.21.x

Identifiers

  • CVE-2026-78329
  • GHSA-v7h8-xhh6-gfj4

Timeline

  • 2026-08-24: disclosed: Vulnerability disclosed via GitHub Advisory GHSA-v7h8-xhh6-gfj4 and CVE-2026-78329
  • 2026-08-24: patched: Patches released: version 4.14.9 (LTS), 4.18.4, and 4.22.0

References

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