CVE-2023-0871: XXE injection in /rtc/post/ endpoint in OpenMNS Horizon 31.0.8 and versions earlier than 32.0.2 on multiple pl

Routine

MEDIUM 5.4UPGRADEUPGRADE

CVE-2023-0871 is a medium-severity flaw (CVSS 5.4) affecting horizon, meridian. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 t

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 54%)
CISA exploited list	No
Weakness	CWE-611
Published	2023-08-11
Last modified	2026-06-17

Publisher (CNA): The OpenNMS Group · Vendor: opennms

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-08-11 17:15 UTCPublished CVE record published
2026-06-17 05:26 UTCUpdated Record last modified

opennms horizon UPGRADE

Affected: >= 32.0.0 and < 32.0.2 · 31.0.8

Fixed in: 32.0.2

Safe to downgrade to: a release before 31.0.8

1. Check installed version

apt-cache policy horizon || rpm -q horizon || horizon --version

2. UPGRADE to 32.0.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade horizon

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade horizon

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 31.0.8 (Debian / Ubuntu)

apt-cache madison horizon sudo apt install horizon=<VERSION_BEFORE_31.0.8> sudo apt-mark hold horizon

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list horizon sudo dnf downgrade horizon-<VERSION_BEFORE_31.0.8> sudo dnf versionlock add horizon

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

opennms meridian UPGRADE

Affected: >= 2020.0.0 and < 2020.1.38 · >= 2021.0.0 and < 2021.1.30 · >= 2022.1.0 and < 2022.1.9 · >= 2023.0.0 and < 2023.1.6

Fixed in: 2020.1.38, 2021.1.30, 2022.1.9, 2023.1.6

Safe to downgrade to: a release before 2020.0.0

1. Check installed version

apt-cache policy meridian || rpm -q meridian || meridian --version

2. UPGRADE to 2020.1.38 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade meridian

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade meridian

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2020.0.0 (Debian / Ubuntu)

apt-cache madison meridian sudo apt install meridian=<VERSION_BEFORE_2020.0.0> sudo apt-mark hold meridian

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list meridian sudo dnf downgrade meridian-<VERSION_BEFORE_2020.0.0> sudo dnf versionlock add meridian

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-0871?

horizon: upgrade to 32.0.2; meridian: upgrade to 2020.1.38, 2021.1.30, 2022.1.9, 2023.1.6. Exact commands for each OS are on this page.

Is CVE-2023-0871 being exploited?

CVE-2023-0871 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-0871 affect?

CVE-2023-0871 affects horizon, meridian. Severity is medium (CVSS 5.4). 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 HT

How urgent is CVE-2023-0871?

Priority 30/100. No elevated risk signals yet.

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References

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