CVE-2026-127235: Reflected Cross-site Scripting Vulnerability Exists
Source GCVE Database
Not known to be exploited · CVSS 6.1 Medium · fixed in 2026.0.2 : update Meridian when convenient.
Data as of 12 Nov 2026, 22:33 UTC
Thin evidence
One scorer or none| CNA (OpenNMS) | CVSS 3.1 | 6.1 |
|---|
- Patch
- Available – fixed in 2026.0.2, 2025.0.12, 2024.3.15 +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 12 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.
What to do
Upgrade Meridian to 2026.0.2, 2025.0.12 or 2024.3.15; Horizon to 36.0.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| The OpenNMS GroupMeridian | Affected
| Fixed in
|
| The OpenNMS GroupMeridian | Affected
| Fixed in
|
| The OpenNMS GroupMeridian | Affected
| Fixed in
|
| The OpenNMS GroupHorizon | Affected
| Fixed in
|
GitHubMeridianpkg:github/MeridianOther threats | Affected
| Fixed in
|
GitHubHorizonpkg:github/HorizonOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade affected OpenNMS Meridian installations to version 2024.3.15, 2025.0.12, 2026.0.2 or later, and Horizon installations to version 36.0.6 or later. These versions include fixes that properly encode reflected request parameters and prevent unsafe client-side template evaluation. Additionally, ensure that OpenNMS web interfaces are not directly accessible from the Internet, as recommended by the installation guidelines.
Description
A reflected cross-site scripting (XSS) vulnerability exists in the web user interface of multiple versions of OpenNMS Meridian and Horizon. The flaw occurs because several web UI pages improperly handle request parameters, allowing an attacker to inject and execute arbitrary JavaScript in the context of an authenticated user's browser session. This enables the attacker to read page data and perform actions with the victim's privileges. The vulnerability is fixed by encoding affected request values and preventing client-side template evaluation on AngularJS pages. Upgrading to Meridian 2024.3.15, 2025.0.12, 2026.0.2 or Horizon 36.0.6 or newer resolves the issue. These products are intended for private network use and should not be exposed directly to the Internet.