CVE-2025-40891: HTML injection in in Time Machine functionality in Guardian/CMC before 25.5.0

Published Dec 18, 2025
·
Updated

A Stored HTML Injection vulnerability was discovered in the Time Machine Snapshot Diff functionality due to improper validation of network traffic data. An unauthenticated attacker can send specially crafted network packets at two different times to inject HTML tags into asset attributes across two snapshots. Exploitation requires a victim to use the Time Machine Snapshot Diff feature on those specific snapshots and perform specific GUI actions, at which point the injected HTML renders in their browser, enabling phishing and open redirect attacks. Full XSS exploitation is prevented by input validation and Content Security Policy. Attack complexity is high due to multiple required conditions.

Affected Software

3 affected components
Guardian CMC<25.5.0
Nozominetworks Cmc<25.5.0
Nozominetworks Guardian<25.5.0

Remediation

Information

Upgrade to v25.5.0 or later.

Event History

Dec 18, 2025
CVE Published
via MITRE·01:14 PM
Data Sourced
via MITRE·01:14 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·02:15 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2025-40891?

CVE-2025-40891 is classified as a high severity vulnerability due to the potential for stored HTML injection.

2

How do I fix CVE-2025-40891?

To fix CVE-2025-40891, it is recommended to update the Guardian CMC software to a version above 25.5.0.

3

Who is affected by CVE-2025-40891?

CVE-2025-40891 affects users of Guardian CMC versions up to 25.5.0.

4

What type of attack is enabled by CVE-2025-40891?

CVE-2025-40891 allows unauthenticated attackers to perform stored HTML injection through specially crafted network packets.

5

What are the potential impacts of CVE-2025-40891?

The potential impacts of CVE-2025-40891 include unauthorized manipulation of web page content and possible phishing attacks.

Contact

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