Security readout for executives and security teams
Plain-English summary
Nagios XI, a network monitoring product, contains a flaw in its Core Config Manager that lets a logged-in user craft a link or input that runs unwanted scripts in another user's browser. An attacker would need to trick a Nagios user into clicking a malicious link to abuse it. Impact is limited to browser-side actions like session hijacking or interface tampering, not direct server takeover.
Executive priority
Schedule a planned upgrade in the next maintenance window. Treat as moderate, not emergency: exploitation requires an authenticated user and victim interaction, and there is no evidence of active abuse, but the fix is straightforward and reduces risk to monitoring administrators.
Technical view
Reflected XSS in the Core Config Manager (CCM) Test Command feature in Nagios XI before 5.8.6 / CCM 3.1.4. Insufficient input validation or output encoding allows attacker-supplied script to execute in the victim's browser context. CVSS 4.0 5.1 (AV:N/AC:L/PR:L/UI:P) reflects authenticated, user-interaction-required exploitation with low confidentiality and integrity impact on a separate security scope. Mapped to CWE-79 and CWE-116.
Likely exposure
Organizations running Nagios XI versions earlier than 5.8.6 with CCM versions earlier than 3.1.4, particularly where the management interface is reachable by multiple internal users or exposed beyond a tightly controlled admin network. Internet-facing Nagios XI portals materially increase exposure.
Exploitation context
No public evidence of active exploitation and the CVE is not in CISA KEV. Exploitation requires an authenticated CCM user to be lured into triggering a crafted Test Command request, then a victim's browser to render the response. No public proof-of-concept or weaponized payload is referenced in the cited sources.
Researcher notes
CWE-79 reflected XSS through the CCM Test Command parameter, fixed in CCM 3.1.4 / Nagios XI 5.8.6. CVSS 4.0 vector indicates PR:L and UI:P, so attack chains likely combine a phishing lure with a logged-in admin session. Subsequent (SC:L/SI:L) scope changes suggest impact extends to the rendering browser context. Validate by version comparison and reviewing vendor changelog; VulnCheck advisory provides additional third-party context.
Mitigation direction
- Upgrade Nagios XI to 5.8.6 or later and CCM to 3.1.4 or later per vendor release notes.
- Restrict CCM access to a small set of trusted administrators using role-based access controls.
- Place the Nagios XI web interface behind a VPN or IP allowlist; do not expose to the public internet.
- Enforce strong session settings and short idle timeouts for Nagios XI accounts.
- Train Nagios operators to avoid clicking unsolicited links pointing at internal monitoring URLs.
Validation and detection
- Confirm the installed Nagios XI version and CCM version against the fixed releases (XI 5.8.6 / CCM 3.1.4).
- Review the Nagios XI changelog to verify the CCM Test Command fix is present in your build.
- Audit web access logs for unusual GET/POST requests to CCM Test Command endpoints with script-like parameters.
- Inventory which user accounts hold CCM privileges and remove unnecessary access.
- Validate that the Nagios XI portal is not reachable from untrusted networks via an external scan.
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-116: 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 lookupCWE-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-2021-47694 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-reflected-xss-via-test-commandCVE 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 Encoding or Escaping of Output
Improper Encoding or Escaping of Output represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
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.