CVE-2020-6820

Mozilla Firefox And Thunderbird Use-After-Free Vulnerability

Severity Score

8.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

Yes

*KEV

Decision

*SSVC

Descriptions

Under certain conditions, when handling a ReadableStream, a race condition can cause a use-after-free. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1.

Bajo determinadas condiciones, cuando se maneja un ReadableStream, una condición de carrera puede causar un uso de la memoria previamente liberada. Somos conscientes de los ataques dirigidos "in the wild" que abusan de este fallo. Esta vulnerabilidad afecta a Thunderbird versiones anteriores a 68.7.0, Firefox versiones anteriores a 74.0.1 y Firefox ESR versiones anteriores a 68.6.1.

A flaw was found in Mozilla's Firefox. A race condition can occur when handling a ReadableStream causing a use-after-free memory issue. The highest threat from this vulnerability are to data confidentiality and integrity as well as system availability.

Mozilla Firefox and Thunderbird contain a race condition vulnerability when handling a ReadableStream under certain conditions. The race condition creates a use-after-free vulnerability, causing unspecified impacts.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-01-10 CVE Reserved
2020-04-06 CVE Published
2021-11-03 Exploited in Wild
2022-05-03 KEV Due Date
2024-02-27 EPSS Updated
2024-08-04 CVE Updated
---------- First Exploit

CWE

CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-416: Use After Free

CAPEC

References (5)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://usn.ubuntu.com/4335-1	2022-07-12
https://www.mozilla.org/security/advisories/mfsa2020-11	2022-07-12
https://www.mozilla.org/security/advisories/mfsa2020-14	2022-07-12
https://access.redhat.com/security/cve/CVE-2020-6820	2020-04-16
https://bugzilla.redhat.com/show_bug.cgi?id=1820878	2020-04-16

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"				< 74.0.1 Search vendor "Mozilla" for product "Firefox" and version " < 74.0.1"		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				< 68.6.1 Search vendor "Mozilla" for product "Firefox Esr" and version " < 68.6.1"		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				< 68.7.0 Search vendor "Mozilla" for product "Thunderbird" and version " < 68.7.0"		-		Affected