---
id: CVE-2026-59321
title: >-
  A single ScriptEngine instance is reused for every message on a script-backed
  channel
summary: >-
  A single ScriptEngine instance is reused for every message on a script-backed
  channel. For JSR-223 engines that report THREADING=null (not thread-safe, e.g.
  the Kotlin kts engine), concurrent message processing can corrupt
  engine-interna…
severity: medium
cvss: 4.2
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-362
published: '2026-08-27'
updated: '2026-08-28'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-59321'
references:
  - url: 'https://spring.io/security/cve-2026-59321'
    label: security@vmware.com
tags:
  - nvd
epss: 0.00127
epssPercentile: 0.0275
ingestedAt: '2026-08-29T21:42:36.096Z'
---

## Overview

A single ScriptEngine instance is reused for every message on a script-backed channel. For JSR-223 engines that report THREADING=null (not thread-safe, e.g. the Kotlin kts engine), concurrent message processing can corrupt engine-internal state, potentially leaking one message's payload/headers bindings into another message's script evaluation or throwing spurious exceptions.
Spring Integration 7.1.0
Spring Integration 7.0.0 - 7.0.5
Spring Integration 6.5.0 - 6.5.10
Spring Integration 6.4.0 - 6.4.12
Spring Integration 5.5.21 and earlier

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.