NN-2026:5-01
HTML injection in Users in Guardian/CMC before 26.1.0
| Advisory ID | NN-2026:5-01 |
|---|---|
| Topic | HTML injection in Users in Guardian/CMC before 26.1.0 |
| CWE Impact | CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') |
| Issue date | 2026-05-19 |
| Affects | Guardian, CMC < v26.1.0 |
| CVE Name(s) | CVE-2025-40902 |
| CVSS Details | 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 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L |
| CVSS Score | 4.8 (CVSS v4.0) 5.9 (CVSS v3.1) |
| CVE Risk Level | Medium (CVSS v4.0) Medium (CVSS v3.1) |
| Risk Level for Nozomi customers | Low |
Summary
A Stored HTML Injection vulnerability was discovered in the Users functionality due to improper validation of an input parameter.
Impact
An authenticated user with administrative privileges can create a malicious user whose username contains HTML tags. When a victim attempts to delete a group containing the affected user, 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.
Affected Products
Guardian, CMC < v26.1.0
Workarounds and Mitigations
Use internal firewall features to limit access to the web management interface. Review all accounts with administrative access to it and delete unnecessary ones. Review usernames of existing users.
Solutions
Upgrade to v26.1.0 or later.
Modification History
Related Links
Acknowledgements
We thank the following parties for their efforts:
- Stefano Libero, Andrea Palanca of Nozomi Networks Product Security team for finding this issue during an internal investigation
Contact
Nozomi Networks Product Security team can be reached at prodsec@nozominetworks.com.More contact details on the PSIRT page.