CVE-2026-53421
Admin-entitled RCE via Groovy-scripted connectors in Apache Syncope.
Is CVE-2026-53421 being exploited?
Not confirmed. CVE-2026-53421 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.68% probability of exploitation in the next 30 days.
How severe is CVE-2026-53421?
CVE-2026-53421 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-53421?
Yes. A fix has been recorded for CVE-2026-53421. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-53421 affect?
CVE-2026-53421 affects Apache Syncope 3.0.0-M0 through 3.0.16, Apache Syncope 4.0.0-M0 through 4.0.6, Apache Syncope 4.1.0-M0 through 4.1.1, Connector subsystem (scripted REST/SQL Groovy connectors). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-53421?
Upgrade to Syncope 4.0.7 or 4.1.2; restrict admin rights and audit/disable scripted connectors.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
An admin with entitlements can execute arbitrary code remotely via REST/SQL Groovy connectors, enabling server compromise and data access.
Immediate action required
- affected>= 3.0.0-M0 and <= 3.0.16
- affected>= 4.0.0-M0 and <= 4.0.6
- affected>= 4.1.0-M0 and <= 4.1.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.