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CVE Record

CVE-2025-40899: Stored Cross-Site Scripting (XSS) in Assets and Nodes in Guardian/CMC before 26.0.0

A Stored Cross-Site Scripting vulnerability was discovered in the Assets and Nodes functionality due to improper validation of an input parameter. An authenticated user with custom fields privileges can define a malicious custom field containing a JavaScript payload. When the victim views the Assets or Nodes pages, the XSS executes in their browser context, allowing the attacker to perform unauthorized actions as the victim, such as modify application data, disrupt application availability, and access limited sensitive information.

HighCVSS 8.9Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2025-40899 is a stored XSS issue in Nozomi Networks Guardian and CMC before 26.0.0. An authenticated user with custom-field privileges can save malicious script content that runs when another user opens Assets or Nodes pages. This could let the attacker act as the victim inside the application.

Executive priority

Treat this as a high-priority remediation for environments using Guardian or CMC, especially in operational technology monitoring contexts. The issue requires authentication, but successful abuse could let a lower-privileged user manipulate the application through a more privileged victim.

Technical view

The issue is CWE-79 improper input validation in Assets and Nodes custom fields. CVSS 3.1 is 8.9, with network access, low attack complexity, low privileges, required user interaction, and changed scope. Impact is described as limited confidentiality loss with high integrity and availability impact.

Likely exposure

Exposure is likely limited to organizations running Nozomi Networks Guardian or CMC before 26.0.0 where authenticated users can define custom fields and other users view Assets or Nodes pages.

Exploitation context

The bundle does not cite active exploitation, and KEV status is false. Exploitation requires an authenticated user with custom-field privileges and a victim viewing affected pages. Stored placement raises concern because privileged users may later trigger the script in their browser context.

Researcher notes

Primary signals are the CVE record, CVSS vector, Nozomi advisory, and Siemens advisory. The source bundle identifies Guardian and CMC before 26.0.0, but its affected-version encoding is sparse, so exact version scoping should be validated against vendor guidance.

Mitigation direction

  • Upgrade Guardian and CMC to 26.0.0 or vendor-advised fixed versions.
  • Review Nozomi and Siemens advisories for exact affected-version guidance.
  • Restrict custom-field privileges to trusted administrative users.
  • Remove or sanitize suspicious custom fields in Assets and Nodes.
  • Monitor application audit logs for unexpected data changes or availability-impacting actions.

Validation and detection

  • Inventory deployed Guardian and CMC versions and compare against vendor advisories.
  • Confirm whether custom-field privileges are assigned to non-administrative users.
  • Review Assets and Nodes custom fields for embedded script-like content.
  • Check logs for recent custom-field creation or modification by unusual accounts.
  • After remediation, verify Assets and Nodes pages render custom fields safely.
Prepared
Confidence
high
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2025-40899 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.9 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
3Timeline events
2ADP providers
3Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.9CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:H2.36Nozomi
7.1CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:H/VA:H/SC:L/SI:L/SA:L——Nozomi

Vulnerability scoring details

Base CVSS 4.0 score

7.1High
CVSS 4.0 vector shape for CVE-2025-40899Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:H/VA:H/SC:L/SI:L/SA:L

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Nozomi NetworksGuardian0unaffected
Nozomi NetworksCMC0unaffected
Weakness

CWE details

CWE-79

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.