In Microchip MPLAB Net 3.6.1, TCP ISNs are improperly random.
Conclusion & alert: CVE-2020-27636 is rated Moderate Risk (50.5/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.18%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
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 | 2025-11-21 | 0.30% | 0.18% | -0.12% |
| 2 | 2025-11-18 | 0.18% | 0.30% | +0.12% |
| 3 | 2025-03-19 | — | 0.18% | — |
Full EPSS history (5 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.1 | 3.1 | CRITICAL |
|
3.9 | 5.2 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| microchip | mplab_network_creator | 3.6.1 | cpe:2.3:a:microchip:mplab_network_creator:3.6.1:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01 | Third Party Advisory US Government Resource |
| https://www.forescout.com | Third Party Advisory |
| https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/ | Third Party Advisory |