Security readout for executives and security teams
Plain-English summary
Older versions of Nagios XI's Core Config Manager have a flaw on the Templates pages that lets an attacker plant malicious code into the interface. If a logged-in administrator views the tampered page, the code runs in their browser and can hijack their session. Upgrading to Nagios XI 5.8.0 or later removes the issue.
Executive priority
Schedule a routine patch cycle: upgrade affected Nagios XI instances and limit who can reach the monitoring console. Risk is moderate, not urgent, but a successful attack could give an intruder a foothold inside the team that watches the rest of your infrastructure.
Technical view
A stored cross-site scripting (CWE-79) weakness exists in the Core Config Manager (CCM) Templates pages of Nagios XI prior to 5.8.0 / CCM 3.1.0. The UI rendering of the Active/Actions controls fails to properly validate or escape user-supplied input, enabling injected script execution in an authenticated victim's browser context. CVSS 4.0 base score is 5.1 (AV:N/AC:L/PR:L/UI:P), reflecting the need for low-privileged access and user interaction.
Likely exposure
Affects organizations running Nagios XI versions earlier than 5.8.0 (CCM earlier than 3.1.0) where the CCM web interface is reachable by authenticated users. Internet-exposed Nagios XI consoles or shared monitoring portals increase exposure. Most current deployments on supported releases should already be remediated, but legacy or air-gapped instances may still be vulnerable.
Exploitation context
No known active exploitation; the CVE is not listed in CISA KEV. Exploitation requires an authenticated low-privileged CCM user to inject script and a victim user to interact with the affected Templates page. Sources do not cite public proof-of-concept code or in-the-wild abuse.
Researcher notes
Stored XSS in an authenticated admin tool is most useful for privilege pivoting and session theft against other CCM users. Validate by enumerating Nagios XI build versions across the estate and confirming whether the Templates Active/Actions UI has been patched. CVSS 4.0 vector includes SC:L/SI:L, indicating limited downstream confidentiality and integrity impact on the victim's browser context.
Mitigation direction
- Upgrade Nagios XI to 5.8.0 or later (CCM 3.1.0+) per vendor changelog.
- Restrict CCM access to trusted administrators and place behind VPN or SSO.
- Enforce least privilege on CCM accounts and review template-edit permissions.
- Apply browser-side defenses such as CSP and HttpOnly session cookies.
- Track Nagios advisories for any follow-on CCM hardening releases.
Validation and detection
- Identify Nagios XI version and CCM version from the admin console banner.
- Compare deployed version against the 5.8.0 / CCM 3.1.0 fixed release.
- Audit CCM user accounts and recent Template page changes for unexpected entries.
- Review web server and application logs for suspicious template submissions.
- Confirm session cookies use HttpOnly and that CSP is enforced on the CCM UI.
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-2021-47689 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-templates-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.