CVE-2026-31981

HTML injection in Diagram tab and Graph view in Guardian/CMC before 26.2.0

Published Jul 9, 2026 CVSS 4.0 · 4.8 Medium EPSS < 1% KEV · Not listed
Description
A Stored HTML Injection vulnerability was discovered in the Diagram tab and Graph view due to a shared input validation function being insufficiently restrictive. An authenticated user with administrative privileges can inject malicious HTML tags into N2OS configuration data through multiple input vectors. When a victim views the affected data in the Diagram tab and Graph view, the injected HTML renders in their browser, enabling phishing and possibly open redirect attacks. Full XSS exploitation and direct information disclosure are prevented by the existing input validation and Content Security Policy configuration.

Analysis

AI-generated

Technical impact

A stored HTML injection flaw exists in the Diagram tab and Graph view of Nozomi Networks’ CMC and Guardian products when running any release earlier than 26.2.0. An authenticated user with administrative privileges can insert malicious HTML tags into N2OS configuration data through multiple input vectors. When another user views the affected data in the diagram or graph view, the injected HTML renders in their browser. This rendering can be used to conduct phishing or open‑redirect attacks, even though full cross‑site scripting exploitation and direct information disclosure are mitigated by existing input validation and Content‑Security‑Policy settings.

Affected Systems

Nozomi Networks’ CMC and Guardian products are vulnerable in any release prior to 26.2.0. The vulnerability affects installations that expose the diagram and graph interfaces to web users.

Risk and Exploitability

The CVSS score of 4.8 places this issue in the medium severity range, and the EPSS score of less than 1% suggests that exploit attempts will be rare. The vulnerability is not listed in the CISA KEV catalog. Attacker must first obtain authenticated administrative access to inject the payload; the subsequent rendering requires a user to view the data. Because the flaw is bounded by current CSP controls, the risk to confidentiality, integrity, and availability is modest, but cosmetic and phishing implications can still be significant for exposed web interfaces.

Remediation

Vendor Solution

Upgrade to v26.2.0 or later.


Vendor Workaround

Use internal firewall features to limit access to the web management interface.


OpenCVE Recommended Actions

  • Upgrade Nozomi Networks CMC and Guardian to version 26.2.0 or later.
  • Configure internal firewalls to restrict access to the web management interface to trusted entities only.
  • Audit and remove any unused administrative accounts to reduce the attack surface.

Generated by OpenCVE AI on August 1, 2026 at 14:51 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A Stored HTML Injection vulnerability was discovered in the Diagram tab and Graph view due to a shared input validation function being insufficiently restrictive. An authenticated user with administrative privileges can inject malicious HTML tags into N2OS configuration data through multiple input vectors. When a victim views the affected data in the Diagram tab and Graph view, the injected HTML renders in their browser, enabling phishing and possibly open redirect attacks. Full XSS exploitation and direct information disclosure are prevented by the existing input validation and Content Security Policy configuration.
Title HTML injection in Diagram tab and Graph view in Guardian/CMC before 26.2.0
First Time appeared Nozomi Networks
Nozomi Networks cmc
Nozomi Networks guardian
Weaknesses CWE-79
CPEs cpe:2.3:a:nozomi_networks:cmc:*:*:*:*:*:*:*:*
cpe:2.3:a:nozomi_networks:guardian:*:*:*:*:*:*:*:*
Vendors & Products Nozomi Networks
Nozomi Networks cmc
Nozomi Networks guardian
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L'}

cvssV4_0

{'score': 4.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L'}

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Sources

Status
PUBLISHED
Assigner
Nozomi
Published
Updated
Aug 11, 2026, 12:23 PM
Reserved
Mar 10, 2026, 4:14 PM
Status
Modified
Published
Jul 9, 2026, 8:16 AM
Modified
Aug 11, 2026, 1:18 PM