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.

Remediation

Vendor Solution

Upgrade to v26.2.0 or later.


Vendor Workaround

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

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

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