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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-53421

Improper Isolation or Compartmentalization vulnerability in Apache Syncope.

CRITICAL 9.8EPSS 1.14%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
1.14% probability · 66th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-653
Affected
apache/syncope
Source
security@apache.org
EPSS trend
0%3%5%27 October 2026: 1.14%27 October 202627 October 2026

EPSS 1.1% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.