Upcoming Advisory — sec-zd-284

Apache Camel: Camel-Vertx-Http: Unsafe Java deserialization of HTTP response bodies via a raw ObjectInputStream when transferException is enabled

Deserialization of Untrusted Data vulnerability in Apache Camel. The camel-vertx-http component deserializes HTTP response bodies carrying the Content-Type application/x-java-serialized-object using a raw java.io.ObjectInputStream, without applying any ObjectInputFilter (VertxHttpHelper.deserializeJavaObjectFromStream) This deserialization path is reached only when the producer endpoint is configured with transferException=true (or the component-level allowJavaSerializedObject=true) and throwExceptionOnFailure is left at its default value of true; in that case a backend HTTP response with a 5xx status and the application/x-java-serialized-object content type has its body deserialized with no class restrictions. An attacker who controls the backend the Camel producer talks to - through a man-in-the-middle position on an unencrypted (plain HTTP) connection, or by compromising the backend service - can return a crafted serialized Java object and, if a suitable gadget chain is present on the classpath, achieve remote code execution on the Camel application host. The path is not reachable in the default configuration, where transferException is false. This issue affects Apache Camel: from 4.0.0 before 4.14.8, from 4.15.0 before 4.18.3, from 4.19.0 before 4.20.0. Users are recommended to upgrade to version 4.20.0, which fixes the issue. If users are on the 4.14.x LTS releases stream, then they are suggested to upgrade to 4.14.8. If users are on the 4.18.x releases stream, then they are suggested to upgrade to 4.18.3. After upgrading, the deserialization performed by both helper utilities is constrained by a default ObjectInputFilter (allow-list java.**;javax.**;org.apache.camel.**;!*), which can be customised through the new deserializationFilter endpoint option or the JVM-wide -Djdk.serialFilter system property. For deployments that cannot upgrade immediately: do not enable transferException=true (or allowJavaSerializedObject=true) on producers that talk to untrusted or network-reachable backends; ensure producer connections use TLS (https) so that a response cannot be substituted by a man-in-the-middle; and, where the option is required, set an explicit -Djdk.serialFilter allow-list (for example java.**;org.apache.camel.**;!*) to constrain deserialization.

CVE IDCVE-2026-40859

CVSS v3.18.1 High

VendorApache

CWECWE-502: Deserialization of Untrusted Data

DisclosedJul 6, 2026

StatusPublished

01/Description

What this actually is.

Technical background, root cause, and affected surface.

The camel-vertx-http and camel-netty-http components deserialize HTTP response bodies with Content-Type application/x-java-serialized-object using a raw java.io.ObjectInputStream without any ObjectInputFilter. The path is reached only when the producer endpoint uses transferException=true (or component-level allowJavaSerializedObject=true) with the default throwExceptionOnFailure=true; a backend 5xx response with that content type is then deserialized with no class restrictions.

Product: Apache Camel
Vendor: Apache
Severity: High
CVSS Score: 8.1
Status: Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE: CWE-502: Deserialization of Untrusted Data

02/Proof of Concept

From one request
to root shell.

Reproduced in a sandboxed environment. Requires only LAN or WiFi adjacency.

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

ScopeUnchanged

ImpactC:H / I:H / A:H

SeverityHigh

PoC · Exploitation Steps▲ trigger

01No public PoC available

03/Vulnerable Code

The bug, and the fix.

VertxHttpHelper.deserializeJavaObjectFromStream() and NettyHttpHelper.deserializeJavaObjectFromStream() - raw java.io.ObjectInputStream.readObject() on response body without ObjectInputFilter

04/Impact

What an attacker does to you.

Post-exploitation outcomes mapped to CVSS impact metrics.

High

Remote code execution on the Camel application host

CIA Impact

C:H · I:H · A:H

CWE-502: Deserialization of Untrusted Data

05/Remediation

Fix it. In this order.

A runbook, not a checklist. Sequence matters — assume compromise before you act.

Upgrade to Apache Camel 4.20.0 (or 4.14.8 / 4.18.3 on LTS streams), which applies a default ObjectInputFilter (java.;javax.;org.apache.camel.**;!*) configurable via the deserializationFilter option. Until upgraded, do not enable transferException/allowJavaSerializedObject and use TLS to backends.

N/A

Securin advisory — For coordinated remediation support or threat-actor briefings related to CVE-2026-40859, contact disclose@securin.io

06/Disclosure Timeline

Vendors moved in days.
Attackers in hours.

Reconstructed from vendor advisories, CISA bulletins, and Securin research records.

2026-04-13

Reported to vendor

2026-04-23

Fixed release published (4.20.0 (4.14.8 for 4.14.x LTS, 4.18.3 for 4.18.x))

2026-07-06

CVE published to MITRE

Disclosed 10 days after discovery

07/References

Cite, verify, go deeper.

Primary sources — NVD, CISA KEV, and machine-readable IoC feed.

NVD

NVD — CVE-2026-40859

nvd.nist.gov/vuln/detail/CVE-2026-40859 →

SEC

Securin VI — Full Technical Analysis

vi.securin.io →

APACHE

https://camel.apache.org/security/CVE-2026-40859.html

https://camel.apache.org/security/CVE-2026-40859.html →

CVE

https://www.cve.org/CVERecord?id=CVE-2026-40859

https://www.cve.org/CVERecord?id=CVE-2026-40859 →

NIST

https://nvd.nist.gov/vuln/detail/CVE-2026-40859

https://nvd.nist.gov/vuln/detail/CVE-2026-40859 →