Skip to content
Noroxi
CVE.org (no NVD analysis yet)· CNA OpenNMS

CVE-2026-111235: OpenNMS REST authorization bypass via non-canonical HTTP method

CriticalCVSS 9.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.37% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: The OpenNMS Group Horizon 36.0.5; The OpenNMS Group Meridian 2024.3.14, 2025.0.11, 2026.0.1.

Low priority for now. Upgrade to The OpenNMS Group Horizon 36.0.5; The OpenNMS Group Meridian 2024.3.14, 2025.0.11, 2026.0.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Oct 15, 2026
Updated
Oct 16, 2026
EPSS
0.3% · 32th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · OpenNMS
9.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-111235

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for the opennms group records
Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (OpenNMS). Independent of NVD's CPE analysis and usually ahead of it.

  • The OpenNMS Group Horizon

    • 36.0.0 and later · before 36.0.5affected · maven

  • The OpenNMS Group Meridian

    • 2024.1.0 and later · before 2024.3.14affected · maven
    • 2025.0.0 and later · before 2025.0.11affected · maven
    • 2026.0.0 and later · before 2026.0.1affected · maven

Same product

the opennms group: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-111252OpenNMS denial of service via XML entity expansion
    26Monitor
  • CVE-2026-89089OpenNMS SQL injection in shipped Asset Management JasperReports via the DATE_FORMAT parameter (ROLE_USER)
    26Monitor
  • CVE-2026-127235OpenNMS reflected cross-site scripting in the web UI via request parameters
    24Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-19182Aug 13, 2026 · OpenNMS v2 Alarm REST API inverted authorization check lets ROLE_REST users acknowledge alarms as any user and bypass read-only
    17Monitor
  • ← EarlierCVE-2026-19596Sep 10, 2026 · OpenNMS XML collector XXE allows arbitrary file read from the OpenNMS host
    23Monitor
  • Later →CVE-2026-127236Nov 12, 2026 · OpenNMS argument injection in ad-hoc RRD graphs
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
The OpenNMS Group Horizon36.0.5Vendor (CNA)
The OpenNMS Group Meridian2024.3.14Vendor (CNA)
The OpenNMS Group Meridian2025.0.11Vendor (CNA)
The OpenNMS Group Meridian2026.0.1Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+29 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-8908935 days apartOpenNMS SQL injection in shipped Asset Management JasperReports via the DATE_FORMAT parameter (ROLE_USER)
    26Monitor
  • CVE-2026-12723628 days apartOpenNMS argument injection in ad-hoc RRD graphs
    21Monitor

Not on record for this CVE: public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-204 · Observable Response Discrepancy

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. SSVC exploitation— → none
  2. Exploit maturity— → none
  3. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records