CVE-2019-11763: Failure to correctly handle null bytes when processing HTML entities resulted in Firefox incorrectly parsing these entities

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 vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

Required

Confidentiality

Low

Integrity

Low

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)1.1% · higher than 67% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

FI

Firefox · Mozilla

before 70.0 · source: NVD

FE

Firefox Esr · Mozilla

before 68.2 · source: NVD

TH

Thunderbird · Mozilla

before 68.2 · source: NVD

UL

Ubuntu Linux · Canonical

16.04 · source: NVD