CVE-2026-53435: Jenkins arbitrary type deserialization in config.xml processing

CVE-2026-53435 · Severity: high · CVSS 8.8 · Published 2026-06-10

Jenkins is an open-source automation server used to orchestrate build pipelines and continuous deployment workflows. An attacker with low-level permissions can submit a specially crafted configuration file that causes Jenkins to deserialize malicious data, allowing them to impersonate any user, execute arbitrary code via the Script Console, or read sensitive files from the server. This provides a direct path to complete system compromise and credential theft.

Technologies: Jenkins, org.jenkins-ci.main:jenkins-core (Maven). Vendors: Jenkins, Maven.

Quick answers

Is CVE-2026-53435 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-53435 being exploited in the wild.
How severe is CVE-2026-53435?
High severity, with a CVSS score of 8.8, published 10 June 2026.
Which products and versions are affected?
Jenkins < 2.555.3, >= 2.556 < 2.568; org.jenkins-ci.main:jenkins-core (Maven) ECOSYSTEM:introduced=0,fixed=2.555.3.
Is there a fix for CVE-2026-53435?
Yes. org.jenkins-ci.main:jenkins-core (Maven): upgrade to 2.555.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-53435 attacked?
It is attacked over the network.
Am I affected by CVE-2026-53435?
Check whether you run Jenkins or org.jenkins-ci.main:jenkins-core (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.jenkins-ci.main:jenkins-core (Maven): upgrade to 2.555.3 or later
    # set org.jenkins-ci.main:jenkins-core to 2.555.3 in your pom.xml or build.gradle

Technical details

This is a CWE-502 unsafe deserialization vulnerability in Jenkins' configuration handling. Jenkins uses XStream for serialization/deserialization of configuration files, and implements a custom filter (JEP-200) to restrict deserialization to known-safe types. However, versions 2.567 and earlier (LTS 2.555.2 and earlier) permit deserialization of any type defined in Jenkins core or plugins from attacker-controlled config.xml submissions. An attacker with Overall/Read permission plus either a user account or config.xml POST capability (e.g., Item/Configure, View/Configure, Agent/Configure) can craft a config.xml payload containing arbitrary types with attacker-controlled behavior. These deserialized objects can then intercept HTTP requests due to Jenkins' Stapler web framework routing, enabling user impersonation, Script Console access for RCE, and arbitrary file disclosure. Jenkins 2.568 and LTS 2.555.3 restrict deserialization to expected types only.

Affected products

  • Jenkins jenkins-core < 2.555.3, >= 2.556 < 2.568

Identifiers

  • CVE-2026-53435
  • GHSA-g2xq-2v27-4rh3

Timeline

  • 2026-06-10: disclosed
  • 2026-06-10: patched: Jenkins 2.568 and LTS 2.555.3 released

References

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