# CVE-2026-59321: Shared JSR-223 ScriptEngine evaluated concurrently without THREADING check

> Concurrent message processing in Spring Integration can leak script bindings or cause exceptions due to unsafe shared ScriptEngine usage.

- **Severity:** Medium 4.2 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-jwww-wmvq-qm8j

## What is CVE-2026-59321?

CVE-2026-59321 is a medium-severity vulnerability in Spring Integration, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-59321?

It affects 1 product.


Products: Vmware Spring Integration.

## How do I fix CVE-2026-59321?

Upgrade to a fixed version.

## Is CVE-2026-59321 being exploited?

There is no known exploitation of CVE-2026-59321 in the wild and no public exploit code.

## Other vulnerabilities in Spring Integration

- [CVE-2026-59324](https://insights.sbomify.com/CVE-2026-59324/): fluxTransform shared RequestMessageHolder causes cross-message header leakage under async fluxFunction (high 8.2)
- [CVE-2026-59307](https://insights.sbomify.com/CVE-2026-59307/): Deserialization allow-list silently bypassed: setBeanClassLoader replaces deserializer but mapper keeps stale reference (high 8.0)
- [CVE-2026-40987](https://insights.sbomify.com/CVE-2026-40987/): Spring Integration File Support: FTP/SFTP/SMB server can write arbitrary files anywhere on the client filesystem (high 7.1)
- [CVE-2026-59311](https://insights.sbomify.com/CVE-2026-59311/): Fixed predictable /tmp/ziptransformer work directory enables symlink pre-creation (medium 6.8)
- [CVE-2026-59293](https://insights.sbomify.com/CVE-2026-59293/): SMB minimum protocol dialect defaults to SMB1 (medium 6.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59321 and fix it if it is affected.

What it is: CVE-2026-59321 is a medium-severity vulnerability in Spring Integration, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-59321 in the wild and no public exploit code.

Affected product: Spring Integration. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-59321/ (Markdown: https://insights.sbomify.com/CVE-2026-59321/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59321
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59321
- OSV: https://osv.dev/vulnerability/CVE-2026-59321

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59321/
Summaries are generated and may contain mistakes; the official description above is the record.