Security readout for executives and security teams
Plain-English summary
Older versions of Nagios Fusion, an IT monitoring dashboard, can be tricked into running attacker-supplied scripts in a logged-in user's browser. An attacker who lures an authenticated user to a crafted link could hijack their session view or steal information visible in the dashboard. The vendor fixed this in version 4.1.5.
Executive priority
Patch on the next standard maintenance window. This is a moderate, authenticated XSS in a monitoring tool, not a remote takeover bug, but Fusion typically holds privileged operational visibility, so an upgrade should be planned promptly rather than deferred.
Technical view
CVE-2018-25119 is a reflected/stored cross-site scripting flaw (CWE-79) in Nagios Fusion before 4.1.5, triggered through the "fusionwindow" parameter due to insufficient input validation or output encoding. CVSS 4.0 base score is 5.1 with low-privilege authentication and user interaction required. Successful exploitation executes attacker JavaScript in the victim's browser session within the Fusion application context.
Likely exposure
Organizations running Nagios Fusion instances older than 4.1.5, particularly those with the web UI exposed to internal users or, riskier still, accessible from untrusted networks. Multi-tenant or NOC environments where many operators share the dashboard increase blast radius.
Exploitation context
No public reports of active exploitation and the issue is not on CISA's KEV list per the source bundle. Exploitation requires a low-privileged authenticated user to interact with a crafted link or content. No public proof-of-concept is referenced in the supplied sources.
Researcher notes
Vector indicates network-reachable, low-privilege authenticated access with user interaction (CVSS:4.0 AV:N/AC:L/PR:L/UI:P) and limited confidentiality/integrity impact on the subsequent system. The fusionwindow parameter is the documented sink; validate by reviewing how Fusion renders this parameter pre- and post-4.1.5 in lab. No KEV listing and no exploit references in the supplied bundle.
Mitigation direction
- Upgrade Nagios Fusion to version 4.1.5 or later per vendor changelog.
- Restrict Fusion web UI access to trusted networks via VPN or allow-listed IPs.
- Enforce least-privilege roles and unique accounts for Fusion operators.
- Apply browser-side defenses: modern browsers, CSP if supported, and short session timeouts.
- Train operators to avoid following unsolicited Fusion links from untrusted sources.
Validation and detection
- Inventory all Nagios Fusion deployments and record installed versions.
- Compare installed versions against the 4.1.5 fix line in the Nagios changelog.
- Review web access logs for unusual fusionwindow parameter values or external referrers.
- Confirm patched instances no longer reflect unencoded script payloads in test traffic.
- Verify network exposure of Fusion endpoints from outside trusted segments.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-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.
Open ATT&CK lookupCVE-2018-25119 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.1 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
5.1MediumVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.nagios.com/changelog/nagios-fusion/CVE reference · release-notes, patch
- https://www.vulncheck.com/advisories/nagios-fusion-xss-via-fusionwindow-parameterCVE reference · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.