Tor Browser before 8.0.1 has an information exposure vulnerability. It allows remote attackers to detect the browser's UI locale by measuring a button width, even if the user has a "Don't send my language" setting.
Conclusion & alert: CVE-2019-12383 is rated Moderate Risk (42.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.74%). 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 | 0.60% | 0.74% | +0.13% |
| 2 | 2025-11-18 | 0.74% | 0.60% | -0.13% |
| 3 | 2025-03-30 | — | 0.74% | — |
Full EPSS history (10 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 4.3 | 3.1 | MEDIUM |
|
2.8 | 1.4 | [email protected] |
| 4.3 | 2.0 | MEDIUM |
|
8.6 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2019-12383 unimportant priority: Debian including 2 source packages (firefox, firefox-esr), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 6. | https://security-tracker.debian.org/tracker/CVE-2019-12383 |
ubuntu
|
medium | CVE-2019-12383 medium priority: Ubuntu including 6 source packages (firefox, firefox-esr, mozjs38, mozjs52, mozjs60, thunderbird), 36 status rows across 6 suites (bionic, cosmic, disco, trusty, upstream, xenial): not-affected 20, DNE 16. | https://ubuntu.com/security/CVE-2019-12383 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| torproject | tor_browser | < 8.0.1 | cpe:2.3:a:torproject:tor_browser:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| http://www.securityfocus.com/bid/108484 | Broken Link Third Party Advisory VDB Entry |
| https://gitweb.torproject.org/tor-browser.git/commit/?id=cbb04b72c68272c2de42f157d40cd7d29a6b7b55 | Mailing List Patch Third Party Advisory |
| https://hackerone.com/reports/282748 | Issue Tracking Third Party Advisory |
| https://trac.torproject.org/projects/tor/ticket/24056 | Vendor Advisory |