CVE-2019-11763

Mozilla: Incorrect HTML parsing results in XSS bypass technique

Severity Score

6.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

Si no se manejan correctamente los bytes nulos cuando se procesan entidades HTML, Firefox analiza de manera incorrecta estas entidades. Esto podría haber conllevado a que el texto de comentario HTML fuese tratado como un HTML, lo que podría haber provocado una vulnerabilidad de tipo XSS en una aplicación web bajo determinadas condiciones. También podría haber conllevado a que las entidades HTML sean enmascaradas desde los filtros, permitiendo el uso de entidades para enmascarar los caracteres actuales de interés de los filtros. Esta vulnerabilidad afecta a Firefox versiones anteriores a la versión 70, Thunderbird versiones anteriores 68.2 y Firefox ESR versiones anteriores a la versión 68.2.

A flaw was found in Mozilla Firefox and Thunderbird where null bytes were incorrectly parsed in HTML entities. This could lead to HTML comments being treated as code which could lead to XSS in a web application or HTML entities being masked from filters.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2019-05-03 CVE Reserved
2019-10-23 CVE Published
2024-05-03 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

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

CAPEC

References (7)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://security.gentoo.org/glsa/202003-10	2023-02-03
https://usn.ubuntu.com/4335-1	2023-02-03
https://www.mozilla.org/security/advisories/mfsa2019-33	2023-02-03
https://www.mozilla.org/security/advisories/mfsa2019-34	2023-02-03
https://www.mozilla.org/security/advisories/mfsa2019-35	2023-02-03
https://access.redhat.com/security/cve/CVE-2019-11763	2019-11-06
https://bugzilla.redhat.com/show_bug.cgi?id=1764444	2019-11-06

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Mozilla Search vendor "Mozilla"		Firefox Search vendor "Mozilla" for product "Firefox"				< 70.0 Search vendor "Mozilla" for product "Firefox" and version " < 70.0"		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				< 68.2 Search vendor "Mozilla" for product "Firefox Esr" and version " < 68.2"		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				< 68.2 Search vendor "Mozilla" for product "Thunderbird" and version " < 68.2"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				16.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "16.04"		esm		Affected