Is CVE-2020-1959 actively exploited?

No active exploitation of CVE-2020-1959 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2020-1959 be exploited remotely?

Yes. CVE-2020-1959 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2020-1959?

CVE-2020-1959 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2020-1959

CWE-917Published: May 4, 2020· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2020-1959 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.