VULNOS
All Threat Alerts
criticalCVE Alert
CVE-2026-111235

Critical Vulnerability: CVE-2026-111235

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 mo

Thursday, October 15, 2026Vulnios Threat Intelligence
Share:

Vulnerability Snapshot

CVE-2026-111235 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.

Executive Summary

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

Why It Matters

CVE-2026-111235 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.1/10

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2026-111235.
  • Apply available patches — Visit vendor advisories for the latest security updates.
  • Monitor for exploitation — Check your SIEM/IDS logs for related indicators.

    • Use Vulnios to continuously monitor your exposure to CVE-2026-111235 and similar vulnerabilities.

    References & Sources

  • https://github.com/OpenNMS/opennms/pull/8934

    • How Vulnios Detects This

    Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.

    AI Security Advisor

    Powered by Gemini

    Get AI-powered security recommendations tailored to this specific threat — including risk assessment, detection guidance, MITRE ATT&CK mapping, and actionable remediation steps.

    Sources

    Related Threat Alerts

    Frequently Asked Questions

    What is CVE-2026-111235?

    CVE-2026-111235 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. 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 rule

    Am I affected?

    Affected technology is listed in the Affected Products section above. If your asset inventory contains any of them, assume in-scope until you can prove otherwise.

    How urgent is the response?

    Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.

    How do I remediate?

    Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.

    Where can I track exploitation activity?

    Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2026-111235. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.

    How does Vulnios help with this?

    Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.

    critical

    Protect Your Organization

    Monitor CVEs, scan for vulnerabilities, and get real-time threat alerts — all in one platform.

    Get Started FreeFree Security ScanOSINT Dashboard

    Weekly threat digest

    KEV-listed exploits and vendor advisories, every Monday.

    One email a week. Unsubscribe any time.

    Get instant alerts on Telegram

    Join our public channel for real-time critical CVE alerts.

    Follow @vulnios