# CVE-2026-53421: Apache Syncope: Remote Code Execution via Scripted Connector

> Administrators can achieve remote code execution via Groovy scripts in Apache Syncope's connector subsystem, requiring an upgrade to hardened versions.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Jul 2026
- **Updated:** 21 Jul 2026
- **Also known as:** GHSA-c7pj-2f8j-jc8m

## What is CVE-2026-53421?

CVE-2026-53421 is a critical code injection vulnerability in Apache Syncope, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Isolation or Compartmentalization vulnerability in Apache Syncope.

An administrator with adequate entitlements can achieve remote code execution through the connector subsystem by relying on scripted connectors' (REST and SQL) capability to run Groovy scripts.

This issue affects Apache Syncope: from 3.0.0-M0 through 3.0.16, from 4.0.0-M0 Through 4.0.6, from 4.1.0-M0 through 4.1.1.

Users are recommended to upgrade to version 4.0.7 / 4.1.2, which fix this issue by hardening the Groovy security sandbox.

Weakness: CWE-653 (Improper Isolation or Compartmentalization)

## Which versions are affected by CVE-2026-53421?

It affects 1 product.


Products: Apache Syncope.

## How do I fix CVE-2026-53421?

No fix has been published for CVE-2026-53421 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53421 being exploited?

There is no known exploitation of CVE-2026-53421 in the wild and no public exploit code.

## Other vulnerabilities in Apache Syncope

- [CVE-2026-53405](https://insights.sbomify.com/CVE-2026-53405/): Apache Syncope: Remote Code Execution via Flowable BPMN Groovy ScriptTask (critical 9.8)
- [CVE-2026-57308](https://insights.sbomify.com/CVE-2026-57308/): Apache Syncope: SQL injection vulnerability in Audit Events search (critical 9.8)
- [CVE-2026-62183](https://insights.sbomify.com/CVE-2026-62183/): Apache Syncope: User self-service privilege escalation (critical 9.8)
- [CVE-2026-63071](https://insights.sbomify.com/CVE-2026-63071/): Apache Syncope: RCE via Groovy Sandbox bypass (critical 9.8)
- [CVE-2020-1959](https://insights.sbomify.com/CVE-2020-1959/): Expression Language Injection in Apache Syncope (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53421 and fix it if it is affected.

What it is: CVE-2026-53421 is a critical code injection vulnerability in Apache Syncope, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53421 in the wild and no public exploit code.

Affected product: Apache Syncope. 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-2026-53421/ (Markdown: https://insights.sbomify.com/CVE-2026-53421/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53421
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53421
- OSV: https://osv.dev/vulnerability/CVE-2026-53421

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53421/
Summaries are generated and may contain mistakes; the official description above is the record.