CVE-2021-4140

Mozilla: Iframe sandbox bypass with XSLT

Severity Score

10.0

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.

Fue posible construir un marcado XSLT específico que podría omitir un entorno limitado de iframe. Esta vulnerabilidad afecta a Firefox ESR < 91.5, Firefox < 96 y Thunderbird < 91.5.

The Mozilla Foundation Security Advisory describes this flaw as: It was possible to construct specific XSLT markups that would enable someone to bypass an iframe sandbox.

Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, spoof the browser UI, bypass security restrictions, obtain sensitive information across domains, or execute arbitrary code.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-12-20 CVE Reserved
2022-01-13 CVE Published
2024-08-03 CVE Updated
2024-08-03 First Exploit
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-91: XML Injection (aka Blind XPath Injection)
CWE-1021: Improper Restriction of Rendered UI Layers or Frames

CAPEC

References (6)

URL	Tag	Source

URL	Date	SRC
https://bugzilla.mozilla.org/show_bug.cgi?id=1746720	2024-08-03

URL	Date	SRC

URL	Date	SRC
https://www.mozilla.org/security/advisories/mfsa2022-01	2023-01-03
https://www.mozilla.org/security/advisories/mfsa2022-02	2023-01-03
https://www.mozilla.org/security/advisories/mfsa2022-03	2023-01-03
https://access.redhat.com/security/cve/CVE-2021-4140	2022-01-12
https://bugzilla.redhat.com/show_bug.cgi?id=2039568	2022-01-12

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"				< 96.0 Search vendor "Mozilla" for product "Firefox" and version " < 96.0"		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				< 91.5 Search vendor "Mozilla" for product "Firefox Esr" and version " < 91.5"		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				< 91.5 Search vendor "Mozilla" for product "Thunderbird" and version " < 91.5"		-		Affected