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TI-2026-15924 Aliases CVE-2026-19596GHSA-9hqx-g6f2-rj2p

OpenNMS XML collector XXE allows arbitrary file read from the OpenNMS host

Priority LOW 26CWE-611Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Information disclosure
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-611 and the CVSS impact.

Summary

An XML External Entity (XXE) vulnerability exists in the XML collector of multiple versions of OpenNMS Meridian and Horizon. When OpenNMS collects XML from a source whose response is attacker-controlled (for example a compromised monitored host or an HTTP man-in-the-middle position), the collector's XML parser resolves external entities and external DTDs. This allows an attacker to read files accessible to the OpenNMS service account, including database credentials, and to induce out-of-band requests. The solution is to upgrade to Meridian 2024.3.13, 2025.0.10 and Horizon 36.0.4 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00337 27th percentileScored 2026-11-07
Fix Fixed Meridian (The OpenNMS Group): 2024.3.13, 2025.0.10Horizon (The OpenNMS Group): 36.0.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
The OpenNMS GroupMeridian2024.1.0 to before 2024.3.13; 2025.0.0 to before 2025.0.102024.3.13, 2025.0.10Patch availableCNA
The OpenNMS GroupHorizon36.0.0 to before 36.0.436.0.4Patch availableCNA
  • Meridian VendorThe OpenNMS Group Affected 2024.1.0 to before 2024.3.13; 2025.0.0 to before 2025.0.10 Fixed in 2024.3.13, 2025.0.10 Patch available CNA
  • Horizon VendorThe OpenNMS Group Affected 36.0.0 to before 36.0.4 Fixed in 36.0.4 Patch available CNA

Remediation

  • Fix · CNA Meridian (The OpenNMS Group) Fixed in 2024.3.13, 2025.0.10
  • Fix · CNA Horizon (The OpenNMS Group) Fixed in 36.0.4

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    The OpenNMS Group Horizon 36.0.4

    3 records Highest priority Priority MEDIUM 1 MEDIUM, 2 LOW

    Other records, highest priority first

    • TI-2026-60354 OpenNMS missing authorization on /api/v2 PATCH endpoints allows unauthenticated configuration changesPriority MEDIUM 42
    • TI-2026-60371 OpenNMS SQL injection in shipped Asset Management JasperReports via the DATE_FORMAT parameter (ROLE_USER)Priority LOW 29
    Show all 3 records →
  • Release ·

    The OpenNMS Group Meridian 2024.3.13, 2025.0.10

    2 records Highest priority Priority LOW 2 LOW

    Other records, highest priority first

    • TI-2026-60371 OpenNMS SQL injection in shipped Asset Management JasperReports via the DATE_FORMAT parameter (ROLE_USER)Priority LOW 29
    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-19596
  2. 2026-10-03 Alias added: GHSA-9hqx-g6f2-rj2p

References

Patch 1

  • TI-2021-07941 Cross-site request forgery in OpenNMS CVSS 3.1HIGH 8.8
  • TI-2021-07943 Cross-site scripting in OpenNMS CVSS 3.1MEDIUM 4.8
  • TI-2021-07939 Cross-site scripting in OpenNMS CVSS 3.1MEDIUM 4.8
  • TI-2021-07940 Cross-site request forgery in OpenNMS CVSS 3.1MEDIUM 4.3
  • TI-2015-06530 OpenNMS has a default password of rtc for the rtc account, which makes it easier for… CVSS 2.0HIGH 10.0
  • TI-2026-74978 OpenNMS REST authorization bypass via non-canonical HTTP method CVSS 3.1CRITICAL 9.1
See all 38 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences