Security readout for executives and security teams
Plain-English summary
Older versions of Nagios XI, a popular IT monitoring platform, contain a flaw that lets an attacker sneak malicious scripts into a configuration field. If a logged-in user views the tampered page, the script runs in their browser, potentially hijacking their session or showing fake content. Nagios fixed this in version 5.8.0.
Executive priority
Schedule a planned upgrade within standard patch cycles. This is a moderate-severity browser-side flaw, not a server takeover, but unpatched monitoring tools erode trust in security tooling and can aid attacker pivoting if administrators are targeted.
Technical view
CVE-2021-47696 is a stored/reflected cross-site scripting weakness (CWE-79) in the Business Process Intelligence (BPI) component of Nagios XI before 5.8.0. The product fails to properly validate or encode user-supplied input handled through the BPI config ID, allowing JavaScript injection that executes in a victim's authenticated browser context. CVSS 4.0 base score is 5.1 (medium), requiring low privileges and user interaction.
Likely exposure
Affects Nagios XI deployments running versions earlier than 5.8.0 where the BPI module is enabled and accessible to authenticated users. Internet-exposed Nagios XI consoles increase risk; internal-only deployments still face insider or pivoted-attacker scenarios. No CPE list was published, so confirm exposure by inventorying Nagios XI versions across monitoring infrastructure.
Exploitation context
Not listed in CISA KEV and no public reports of in-the-wild exploitation are cited in the source bundle. Exploitation requires an authenticated low-privilege account plus a victim interaction (clicking or viewing the affected page). The CVSS vector indicates network attack with low complexity, no integrity/availability impact on the vulnerable system but limited subsequent confidentiality and integrity impact via the victim browser.
Researcher notes
XSS sink is the BPI config ID handler; review parameter sanitization and output encoding logic in the BPI controller and template layer. Validate whether the flaw is reflected, stored, or both. CVSS 4.0 vector indicates SC:L/SI:L impact, suggesting session or UI manipulation against the victim browser. No public PoC URL is provided in the source bundle.
Mitigation direction
- Upgrade Nagios XI to version 5.8.0 or later per vendor changelog.
- Restrict BPI module access to trusted, least-privilege accounts only.
- Place Nagios XI behind SSO and network controls to limit unauthenticated reach.
- Apply a WAF rule set that detects script injection patterns on Nagios XI URLs.
- Train monitoring-team users to avoid clicking unexpected BPI links.
Validation and detection
- Inventory all Nagios XI instances and record exact version strings.
- Compare versions against the 5.8.0 fixed release noted in Nagios changelog.
- Review BPI configuration entries for unexpected HTML or script content.
- Check web access logs for suspicious BPI config ID parameters.
- Confirm patch status with vendor support if uncertainty remains.
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-2021-47696 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-bpi-config-id-handlingCVE 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.