OpenNMS REST authorization bypass via non-canonical HTTP method
An authorization bypass vulnerability exists in the REST API of multiple versions of OpenNMS Meridian and Horizon. The /rest/** Spring Security filter chains authorize requests with intercept-url rules that name the HTTP method as an uppercase token, compare the method case-sensitively, and have no terminal deny rule. A request that uses a non-canonical (for example lowercase) method token matches no rule and is processed without authentication. A remote, unauthenticated attacker can read the monitored inventory and can create, modify, or delete resources through the REST API, which includes injecting events to fabricate or suppress alarms. The /rest/alarms chain has the same missing deny rule and discloses whether an alarm exists through a difference in the response. The fix adds a terminal deny rule to each REST filter chain. The solution is to upgrade to Meridian 2024.3.14, 2025.0.11, 2026.0.1 and Horizon 36.0.5 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.
CVE-2026-111235
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-111235
Meridian
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Horizon
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://github.com/OpenNMS",
"vendor": "The OpenNMS Group",
"product": "Meridian",
"versions": [
{
"status": "affected",
"version": "2024.1.0",
"lessThan": "2024.3.14",
"versionType": "maven"
},
{
"status": "affected",
"version": "2025.0.0",
"lessThan": "2025.0.11",
"versionType": "maven"
},
{
"status": "affected",
"version": "2026.0.0",
"lessThan": "2026.0.1",
"versionType": "maven"
}
],
"defaultStatus": "unaffected"
},
{
"repo": "https://github.com/OpenNMS",
"vendor": "The OpenNMS Group",
"product": "Horizon",
"versions": [
{
"status": "affected",
"version": "36.0.0",
"lessThan": "36.0.5",
"versionType": "maven"
}
],
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-111235
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #34402 · Revision 1
- Added to Heist Feed
- Publisher date