CVE-2025-40902Network attack vector

Phishing via stored username HTML injection

Published May 19, 2026 · Updated May 19, 2026

Stored HTML injection in Nozomi Networks Guardian and CMC before 26.1.0 allows remote authenticated users to render HTML in a victim's browser. The Users function stores an administrator-supplied username containing permitted HTML tags and renders it unencoded when a victim deletes the user's group. Administrative access and victim interaction are required; CSP and validation block full XSS and direct data disclosure, limiting impact to phishing or open redirects.

CVSS severity4.8
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored HTML injection in Nozomi Networks Guardian and CMC before 26.1.0 allows remote authenticated users to render HTML in a victim's browser. The Users function stores an administrator-supplied username containing permitted HTML tags and renders it unencoded when a victim deletes the user's group. Administrative access and victim interaction are required; CSP and validation block full XSS and direct data disclosure, limiting impact to phishing or open redirects.

The record

CVE
CVE-2025-40902
Published
May 19, 2026
Updated
May 19, 2026
Vendor
Nozomi Networks
Product
Guardian
Classifications
CWE-79
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. May 19, 2026CVE publishedPublication date reported by the CVE source.
  2. May 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <26.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Nozomi Networks · Guardianversion=0 <26.1.0
Nozomi Networks · Central Management Console (CMC)version=0 <26.1.0

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.8Nozomi Networks Inc.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
5.9Nozomi Networks Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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