Medium

Stored HTML Injection in Nozomi Guardian/CMC Asset List

IdentifiersCVE-2025-40893CWE-79· Improper Neutralization of Input…

CVE-2025-40893 is a stored HTML injection vulnerability in the Asset List functionality of Nozomi Guardian/CMC, including deployments on Siemens RUGGEDCOM APE1808 devices. The issue is caused by improper validation of network traffic data used to populate asset attributes. An unauthenticated attacker can send specially crafted network packets that cause HTML tags to be stored in asset metadata. When a user later views the affected assets in the Asset List or similar interface components, the injected HTML is rendered in the user’s browser. According to the advisory, the existing input validation and Content Security Policy prevent full cross-site scripting exploitation and direct information disclosure, but the rendered HTML can still be abused for phishing and potentially open redirect-style attacks.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated remote attacker to poison asset data so that malicious HTML is persistently rendered to users viewing affected assets in the web interface. The practical impact described is phishing and possible open redirect attacks against operators or other users of the interface. The advisory states that full XSS and direct information disclosure are prevented by existing input validation and CSP, so the impact appears limited primarily to browser-side content injection with low confidentiality and integrity impact and no stated direct availability impact.

Mitigation

If you can’t patch tonight, do this now.

Until patches are available, Siemens recommends protecting network access to affected devices and configuring deployments in accordance with Siemens operational guidelines for Industrial Security. CISA-recommended mitigations include minimizing exposure of control system devices to the internet, isolating control networks behind firewalls, segmenting control systems from business networks, and using secure remote access methods such as fully updated VPNs. Reducing the ability of unauthenticated parties to send crafted network traffic to monitored environments will also reduce exposure.

Remediation

Patch, then assume compromise.

Siemens indicates that fixes are being prepared and advises customers to contact customer support to obtain patch and update information. Apply the vendor-provided fixed version or update as soon as it becomes available for affected Nozomi Guardian/CMC deployments on Siemens RUGGEDCOM APE1808 devices.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Nozomi NetworksCmcapplication

Nozomi NetworksGuardianapplication

NozominetworksCmcapplication

NozominetworksGuardianapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

5 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3