CVE-2019-12383 — Tor Browser before 8

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-05-28T02:21:05.000Z
• Last modified: 2024-08-04T23:17:39.997Z

09References

• trac.torproject.org — https://trac.torproject.org/projects/tor/ticket/24056
• hackerone.com — https://hackerone.com/reports/282748
• gitweb.torproject.org — https://gitweb.torproject.org/tor-browser.git/commit/?id=cbb04b72c68272c2de42f15…
• www.securityfocus.com — http://www.securityfocus.com/bid/108484