CVE-2023-0871: An XML External Entity injection vulnerability

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-08-11 · updated 2026-06-17
Weakness: CWE-611

Description

XXE injection in /rtc/post/ endpoint in OpenMNS Horizon 31.0.8 and versions earlier than 32.0.2 on multiple platforms is vulnerable to XML external entity (XXE) injection, which can be used for instance to force Horizon to make arbitrary HTTP requests to internal and external services. The solution is to upgrade to Meridian 2023.1.6, 2022.1.19, 2021.1.30, 2020.1.38 or Horizon 32.0.2 or newer. Meridian and Horizon installation instructions state that they are intended for installation within an organization's private networks and should not be directly accessible from the Internet. OpenNMS thanks Erik Wynter and Moshe Apelbaum for reporting this issue.

Affected products

The OpenNMS Group Horizon: from 32.0.0 before 32.0.2; 31.0.8 — fixed in 32.0.2
The OpenNMS Group Meridian: from 2020.0.0 before 2020.1.38; from 2021.0.0 before 2021.1.30; from 2022.1.0 before 2022.1.9; from 2023.0.0 before 2023.1.6 — fixed in 2020.1.38, 2021.1.30, 2022.1.9, 2023.1.6

How to fix

Upgrade to a fixed version: The OpenNMS Group Horizon 32.0.2; The OpenNMS Group Meridian 2020.1.38, 2021.1.30, 2022.1.9, 2023.1.6. Check the vendor advisory for mitigations.

References

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