CVE-2019-11763

Description

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.

CVSS Metrics

• v3.1•MEDIUM•Score: 6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• v2.0•MEDIUM•Score: 4.3AV:N/AC:M/Au:N/C:N/I:P/A:N

EPSS Trends

Current EPSS score: 0.80%• Percentile: 74%

Techniques & Countermeasures

• CWE-79•Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

  The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Affected Systems

• canonical•ubuntu_linux

  16.04

• mozilla•firefox

  < 70.0 | < 70

• mozilla•firefox_esr

  < 68.2

• mozilla•thunderbird

  < 68.2

References (6)

• https://www.mozilla.org/security/advisories/mfsa2019-35/
• https://www.mozilla.org/security/advisories/mfsa2019-33/
• https://www.mozilla.org/security/advisories/mfsa2019-34/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1584216
• https://security.gentoo.org/glsa/202003-10
• https://usn.ubuntu.com/4335-1/