XSS in Mozilla Firefox
CVE-2019-11763
Failure to correctly handle null bytes when processing HTML entities resulted in Firefox incorrectly parsing these entities. This could have led to HTML comment text being treated as HTML which could have led to XSS in a web application under certain conditions. It could have also led to HTML entities being masked from filters - enabling the use of entities to mask the actual characters of interest from filters. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.011 (66.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 66.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.011 · change: -0.000
Affected products
- Mozilla Firefox — versions before 70
- Mozilla Firefox Esr — versions before 68.2
- Mozilla Firefox Esr
- Mozilla Thunderbird — versions before 68.2
- Canonical Ubuntu Linux — versions 16.04
Weakness classification (CWE)
References
- www.mozilla.org/security/advisories/mfsa2019-35/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2019-33/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2019-34/ (Vendor Advisory)
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
- security.gentoo.org/glsa/202003-10 (vendor-advisory, Third Party Advisory)
- usn.ubuntu.com/4335-1/ (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2019-11763?
- CVE-2019-11763 is a medium-severity vulnerability in Mozilla Firefox, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-01-08.
- How severe is CVE-2019-11763?
- Medium severity. CVSS v3 base score is 6.1 out of 10.