Security readout for executives and security teams
Plain-English summary
Older versions of Nagios XI, a popular IT monitoring platform, contain a flaw on the status and report pages that lets an attacker sneak malicious script into a link. If a logged-in operator clicks the link, the script runs in their browser and can hijack their session or steal data they can see in the monitoring console.
Executive priority
Schedule a routine patch cycle within the next maintenance window. This is a moderate-severity browser-side flaw that needs a logged-in user to click a malicious link, so it is not an emergency, but unpatched monitoring tools are attractive footholds and should not be left behind.
Technical view
CVE-2011-10040 is a reflected cross-site scripting (CWE-79) weakness in Nagios XI versions prior to 2011R1.9. Link-handling functions on status and report pages fail to adequately validate or escape user-supplied input, allowing arbitrary JavaScript to execute in the victim's authenticated browser session. CVSS 4.0 base score is 5.1 (medium) with network vector, low privileges required, and required user interaction.
Likely exposure
Affects organizations running Nagios XI installations older than 2011R1.9, particularly where the web console is reachable by authenticated operators. Exposure is highest where Nagios XI is internet-facing or where operators routinely follow shared dashboard or report links.
Exploitation context
Not listed in CISA KEV and the source bundle cites no active exploitation. Successful attack requires a low-privileged authenticated user (PR:L) to click a crafted link (UI:P), making targeted phishing of NOC operators the realistic delivery path.
Researcher notes
CVSS 4.0 vector reflects low confidentiality and integrity impact on subsequent systems (SC:L/SI:L) consistent with reflected XSS in an authenticated console. The CVE record lists affected versions as "0" with defaultStatus "unaffected," which is ambiguous; rely on the Nagios changelog and VulnCheck advisory to confirm the 2011R1.9 fix boundary. No public PoC, KEV entry, or exploitation telemetry is cited in the bundle.
Mitigation direction
- Upgrade Nagios XI to version 2011R1.9 or later per the vendor changelog.
- Restrict Nagios XI web console access to trusted networks via VPN or IP allowlists.
- Enforce least-privilege roles so operators cannot share or open arbitrary dashboard links.
- Apply a Content-Security-Policy header at the proxy if upstream patching is delayed.
- Train NOC and operations staff to avoid clicking unsolicited Nagios links from chat or email.
Validation and detection
- Inventory all Nagios XI instances and record installed version against 2011R1.9.
- Review Nagios XI changelog and confirm the patched build is deployed in each environment.
- Test status and report page link parameters in a controlled lab to confirm output encoding.
- Audit web server and reverse-proxy logs for suspicious query strings targeting status or report endpoints.
- Re-run an authenticated web vulnerability scan after patching to confirm the XSS no longer reflects.
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-2011-10040 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-xss-via-status-report-page-link-functionsCVE 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.