Nagios Log Server before 2.1.9 contains Stored XSS in the custom column view for the alert history and audit log function through the affected pp parameter. This affects users who open a crafted link or third-party web page.
Conclusion & alert: CVE-2021-35479 is rated High Exploit Risk (75.7/100): CVSS Medium severity, with high exploitation likelihood (EPSS 48.00%, 98th percentile). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +6.56% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-10-19 | 41.44% | 48.00% | +6.56% |
| 2 | 2025-08-07 | 48.00% | 41.44% | -6.56% |
| 3 | 2025-03-30 | — | 48.00% | — |
Full EPSS history (12 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.4 | 3.1 | MEDIUM |
|
2.3 | 2.7 | [email protected] |
| 3.5 | 2.0 | LOW |
|
6.8 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| nagios | log_server | < 2.1.9 | cpe:2.3:a:nagios:log_server:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://research.nccgroup.com/2021/07/22/technical-advisory-stored-and-reflected-xss-vulnerability-in-nagios-log-server-cve-2021-35478cve-2021-35479/ | Exploit Third Party Advisory |
| https://research.nccgroup.com/?research=Technical%20advisories | Third Party Advisory |
| https://www.nagios.com/downloads/nagios-log-server/change-log/ | Vendor Advisory |