What is the CVSS score of CVE-2026-53421?

CVE-2026-53421 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of Apache Syncope are affected by CVE-2026-53421?

Apache Syncope (identity and connector management platform) versions 3.0.0-3.0.16, 4.0.0-4.0.6, and 4.1.0-4.1.1 contain a critical remote code execution vulnerability in the connector subsystem that…

How to fix or mitigate CVE-2026-53421?

Within 24 hours: inventory all systems running Apache Syncope, document affected versions (3.0.0-3.0.16, 4.0.0-4.0.6, 4.1.0-4.1.1), and assess administrative user access. Within 7 days: implement compensating controls by restricting Syncope administrator role assignments, enabling multi-factor authentication for admin accounts, isolating Syncope administrative interfaces via network segmentation, and enabling detailed audit logging of all administrative actions. Within 30 days: establish a vendor patch monitoring process for Apache Syncope releases, develop an upgrade timeline for affected versions once patches become available, and conduct a privileged access review across all identity management systems.

Apache Syncope CVE-2026-53421

EUVD-2026-45958 CRITICAL

Improper Isolation or Compartmentalization (CWE-653)

2026-07-20 apache

GHSA-c7pj-2f8j-jc8m

RCE Apache Apache Syncope Apache Software Foundation

9.8

CVSS 3.1 · Vendor: apache

Severity by source

Vendor (apache) PRIMARY

9.8 MEDIUM

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

vuln.today AI

7.2 HIGH

Vendor requires an administrator with connector entitlements, so PR:H not PR:N; network-reachable admin API with no added complexity gives AV:N/AC:L, and Groovy RCE yields full C:H/I:H/A:H.

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

4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (apache).

CVSS VectorVendor: apache

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Updated

Jul 21, 2026 - 16:33 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jul 21, 2026 - 16:22 vuln.today

cvss_changed

CVSS changed

Jul 21, 2026 - 16:22 NVD

9.8 (CRITICAL)

Analysis Generated

Jul 20, 2026 - 15:07 vuln.today

DescriptionCVE.org

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.

AnalysisAI

Remote code execution in Apache Syncope's connector subsystem allows an administrator holding sufficient entitlements to run arbitrary Groovy scripts through scripted REST and SQL connectors, escaping the intended sandbox and executing code on the host. It affects Syncope 3.0.0-M0 through 3.0.16, 4.0.0-M0 through 4.0.6, and 4.1.0-M0 through 4.1.1, and is rooted in improper isolation (CWE-653) of the scripting engine. Although the published CVSS is 9.8, the vendor description states an authenticated privileged administrator is required, and there is no public exploit identified at time of analysis.

Technical ContextAI

Apache Syncope is an open-source identity management (IdM/IGA) platform used to provision and synchronize identities across external systems via ConnId-based connectors. Scripted connectors (REST and SQL variants) intentionally support Groovy scripts to transform or route provisioning data, executing them inside a security sandbox. The flaw is CWE-653 (Improper Isolation or Compartmentalization): the Groovy sandbox does not sufficiently confine script execution, so a user permitted to define connector scripts can break out of the intended boundary and reach the underlying JVM/host. The single affected product per CPE is cpe:2.3:a:apache_software_foundation:apache_syncope, and the root cause is insufficient hardening of the Groovy engine rather than a memory-safety or injection defect in a parser.

RemediationAI

Vendor-released patch: upgrade to Apache Syncope 4.0.7 or 4.1.2, which fix the issue by hardening the Groovy security sandbox; 3.0.x users should move to a fixed 4.0.x/4.1.x release since no fixed 3.0.x version is cited in the advisory (confirm the 3.0 upgrade path with Apache). Until patching, reduce the entitlement footprint by removing connector-management and script-editing entitlements from all but a minimal set of trusted administrators, avoid or disable scripted REST and SQL connectors that execute Groovy where they are not operationally required, and restrict network access to the Syncope admin console/core so only trusted management hosts can reach it - noting the trade-off that curtailing scripted connectors may break provisioning workflows that legitimately depend on Groovy transformations. Follow the official advisory at https://lists.apache.org/thread/nmzvz6gb2ldm30wvyk613r8dfrb6r8yx for exact upgrade guidance.