CVE-2025-40891CWE-79cross-site-scripting

CVE-2025-40891

Medium · published December 18, 2025

CVSS v3.1
4.7
EPSS
0%
Percentile
6.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.7 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00175 · 6.6th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2025-12-18T19:15Z
Affected products (2)
ProductVersionsFixed in
nozominetworks/cmc< 25.5.025.5.0
nozominetworks/guardian< 25.5.025.5.0
References (2)
EPSS history
Timeline
  • 18 DEC 13:14Z
    HTML injection in in Time Machine functionality in Guardian/CMC before 25.5.0
    cvelistv5