Apache Syncope: Improper Isolation or Compartmentalization
CVE-2026-53421 is a critical-severity improper isolation or compartmentalization vulnerability in Apache Syncope from Apache, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Syncope versions: 3.0.0-M0 through 3.0.16; 4.0.0-M0 through 4.0.6; 4.1.0-M0 through 4.1.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.14% chance of exploitation within 30 days, higher than 67% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Syncope to 4.0.7 or 4.1.2, whichever matches your release line, or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Syncope | 3.0.0-M0 through 3.0.16; 4.0.0-M0 through 4.0.6; 4.1.0-M0 through 4.1.1 | Not stated |
| Apache | Syncope | 3.0.0 through 3.0.16; 4.0.0 up to, but not including, 4.0.7; 4.1.0 up to, but not including, 4.1.2 | 4.0.7, 4.1.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Isolation or Compartmentalization
The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.
How developers prevent this class of flaw
- Break up privileges between different modules, objects, or entities. Minimize the interfaces between modules and require strong access control between them.
More Improper Isolation or Compartmentalization vulnerabilities (CWE-653)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- openwall.com/lists/oss-security/2026/07/20/7Mailing List, Third Party Advisory
Other vulnerabilities in Apache Syncope
- 9.8 Critical severity
- 9.8 Critical severity
- 9.1 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Isolation or Compartmentalization vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 8.5 High severity
- 7.2 High severity
- 8.8 High severity
- 9.8 Critical severity
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