CVE-2026-53405

Q: How do I fix CVE-2026-53405?

Upgrade syncope to 4.1.2 or later.

Q: Is CVE-2026-53405 being actively exploited?

Not that we know of. CVE-2026-53405 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.45% is the estimated probability that it will be exploited in the next 30 days. That is higher than 37% of all scored CVEs.

Q: How severe is CVE-2026-53405?

CVE-2026-53405 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-53405 affect?

Published advisories record a fix for syncope (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

CRITICAL

9.8

CVSS v3

NVD

Description

Improper Isolation or Compartmentalization vulnerability in Apache Syncope. An administrator with adequate entitlements can import arbitrary BPMN process definitions via the REST API and then start the process. When a BPMN process containing a Groovy scriptTask is imported and started, the Groovy script is executed directly on the server, with no sandbox. 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 wrapping Flowable's Groovy scriptTasks with security sandbox.

CWE-653

How to fix

Remediation Available

syncopeNVD

Affected:>= 4.1.0, < 4.1.2Fixed in:4.1.2CVE-2026-53405derived from NVD

Affected:>= 4.0.0, < 4.0.7Fixed in:4.0.7CVE-2026-53405derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.45%probability of exploitation in 30 days

37thpercentile

Low risk: more likely to be exploited than 37% of all known CVEs.

References

Vendor Advisory1

lists.apache.org

Third-Party Advisory1

openwall.com

Related Vulnerabilities

Other CWE-653 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-1974	Critical	9.8	100%	-	-
CVE-2025-57738	High	7.2	23%	-	Fix
CVE-2025-21590	Medium	4.4	1.7%	KEV	-
CVE-2026-24781	Critical	9.8	1.2%	-	Fix
CVE-2024-0135	High	7.6	1.1%	-	Fix
CVE-2026-43997	Critical	10.0	1.0%	-	Fix

Common questions

How do I fix CVE-2026-53405?

Upgrade syncope to 4.1.2 or later.

Is CVE-2026-53405 being actively exploited?

Not that we know of. CVE-2026-53405 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.45% is the estimated probability that it will be exploited in the next 30 days. That is higher than 37% of all scored CVEs.

How severe is CVE-2026-53405?

CVE-2026-53405 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-53405 affect?

Published advisories record a fix for syncope (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-27.