NoScript Classic before 5.1.8.7, as used in Tor Browser 7.x and other products, allows attackers to bypass script blocking via the text/html;/json Content-Type value.
Conclusion & alert: CVE-2018-16983 is rated High Risk (72.1/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 3.12%). Core evidence: EPSS rose +2.72% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize 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 | 2026-06-15 | 0.40% | 3.12% | +2.72% |
| 2 | 2026-03-04 | 0.49% | 0.40% | -0.09% |
| 3 | 2026-03-01 | — | 0.49% | — |
Full EPSS history (39 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
ubuntu
|
negligible | CVE-2018-16983 negligible priority: Ubuntu including 1 source packages (mozilla-noscript), 4 status rows across 4 suites (bionic, trusty, upstream, xenial): DNE 3, needs-triage 1. | https://ubuntu.com/security/CVE-2018-16983 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| noscript | noscript | < 5.1.8.7 | cpe:2.3:a:noscript:noscript:*:*:*:*:*:*:*:* |
| torproject | tor_browser | >= 7.0.0, <= 7.0.11 | cpe:2.3:a:torproject:tor_browser:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://noscript.net/getit#classic | Release Notes |
| https://twitter.com/Zerodium/status/1039127214602641409 | Third Party Advisory |
| https://www.zdnet.com/article/exploit-vendor-drops-tor-browser-zero-day-on-twitter/ | Third Party Advisory |