Security readout for executives and security teams
Plain-English summary
Nagios XI, a popular IT monitoring tool, contained flaws in its Core Config Manager that could let an attacker plant malicious code on certain admin pages. If a logged-in user viewed a tampered page, their browser could run that code, exposing the monitoring console to misuse. Nagios fixed this in XI 5.7.5 (CCM 3.0.8).
Executive priority
Medium priority. Patch during the next standard maintenance window if Nagios XI is deployed and accessible to multiple administrators. Treat as higher priority if the console is internet-facing or shared with third parties.
Technical view
Multiple stored/reflected XSS issues (CWE-79) exist in CCM overlay rendering and the Notification/Check Period pages in Nagios XI prior to 5.7.5 / CCM 3.0.8. Insufficient input validation or output encoding lets an authenticated low-privilege user inject script that executes in another user's session context. CVSS 4.0 base 5.1 reflects authenticated, user-interaction-required scope.
Likely exposure
Exposure is limited to organizations running Nagios XI versions older than 5.7.5 with CCM exposed to authenticated users. Internet-exposed Nagios XI consoles or shared admin environments increase risk; isolated, fully-patched installs are unaffected per the vendor's default-unaffected scoping.
Exploitation context
No public evidence of active exploitation; CISA KEV does not list this CVE. Exploitation requires an authenticated CCM user to inject payloads and a victim user to view the affected overlay or Notification/Check Period page. No public proof-of-concept is cited in the bundle.
Researcher notes
CWE-79 across multiple CCM views (overlay rendering, Notification Period, Check Period). CVSS 4.0 vector AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N indicates authenticated, victim-interaction-required, with subsequent-system confidentiality and integrity impact only. No CPEs supplied; defaultStatus is "unaffected" so confirm fixed build via vendor changelog. KEV: false. Published 2025-10-30; updated 2025-11-17.
Mitigation direction
- Upgrade Nagios XI to 5.7.5 or later (CCM 3.0.8+) per vendor changelog.
- Restrict CCM access to trusted administrators and enforce least privilege.
- Place the Nagios XI console behind VPN or SSO; do not expose to the internet.
- Review CCM audit logs for unexpected configuration edits in Notification/Check Period objects.
- Apply browser-side hardening (CSP, HttpOnly/SameSite cookies) on the Nagios XI host.
Validation and detection
- Check Nagios XI version in Admin > System Information; confirm 5.7.5 or higher.
- Verify CCM module version is 3.0.8 or later.
- Inventory user accounts with CCM write access and confirm legitimacy.
- Review Notification and Check Period definitions for unexpected HTML or script content.
- Confirm vendor changelog entry for 5.7.5 against deployed build hashes.
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-2020-36861 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-xi/CVE reference · release-notes, patch
- https://www.vulncheck.com/advisories/nagios-xi-ccm-xss-via-overlay-rendering-and-notification-check-period-pagesCVE 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.