CVE-2020-1959

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-05-04 · updated 2026-06-17
Weakness: CWE-917

Description

A Server-Side Template Injection was identified in Apache Syncope prior to 2.1.6 enabling attackers to inject arbitrary Java EL expressions, leading to an unauthenticated Remote Code Execution (RCE) vulnerability. Apache Syncope uses Java Bean Validation (JSR 380) custom constraint validators. When building custom constraint violation error messages, they support different types of interpolation, including Java EL expressions. Therefore, if an attacker can inject arbitrary data in the error message template being passed, they will be able to run arbitrary Java code.

Affected products

Apache Software Foundation Apache Syncope: from 2.1.0 before 2.1.6 — fixed in 2.1.6

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Syncope 2.1.6. Check the vendor advisory for mitigations.

References

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