CVE-2026-111235
CRITICALDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 30% of all known CVEs.
References
Related Vulnerabilities
Other CWE-204 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-41697 | Medium | 5.3 | 20% | - | - |
| CVE-2016-9499 | Medium | 5.3 | 7.7% | - | Fix |
| CVE-2019-19030 | Medium | 5.3 | 1.9% | - | Fix |
| CVE-2021-20049 | High | 7.5 | 1.4% | - | Fix |
| CVE-2022-0564 | Medium | 5.3 | 1.4% | - | Fix |
| CVE-2021-39189 | Medium | 5.3 | 1.4% | - | Fix |
Common questions
How do I fix CVE-2026-111235?
No published fix for CVE-2026-111235 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-111235 being actively exploited?
Not that we know of. CVE-2026-111235 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.38% is the estimated probability that it will be exploited in the next 30 days. That is higher than 30% of all scored CVEs.
How severe is CVE-2026-111235?
CVE-2026-111235 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-111235
Markdown
[](https://tridentstack.com/cve/CVE-2026-111235)HTML
<a href="https://tridentstack.com/cve/CVE-2026-111235"><img src="https://tridentstack.com/cve/badge/CVE-2026-111235.svg" alt="CVE-2026-111235"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-16.