CVE-2025-40904Network attack vector

Authenticated phishing via synced Smart Polling HTML

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 Smart Polling sync accepts HTML tags in a malicious remote strategy and later inserts that strategy into the viewing interface without sufficient validation. Limited privileges suffice to plant the strategy, but a victim must view it; the rendered HTML enables phishing while existing validation and CSP block full XSS and direct disclosure.

CVSS severity5.1
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 Smart Polling sync accepts HTML tags in a malicious remote strategy and later inserts that strategy into the viewing interface without sufficient validation. Limited privileges suffice to plant the strategy, but a victim must view it; the rendered HTML enables phishing while existing validation and CSP block full XSS and direct disclosure.

The record

CVE
CVE-2025-40904
Published
May 19, 2026
Updated
May 19, 2026
Vendor
Nozomi Networks
Product
Guardian
Classifications
CWE-79, T1566
Attack vector
network
Privileges
authenticated

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 privilegesauthenticated

What is affected?

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

Published CVSS scores

6.5Nozomi Networks Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.1Nozomi Networks Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1566Phishing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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