CVE-2020-26974

Mozilla: Incorrect cast of StyleGenericFlexBasis resulted in a heap use-after-free

Severity Score

8.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

When flex-basis was used on a table wrapper, a StyleGenericFlexBasis object could have been incorrectly cast to the wrong type. This resulted in a heap user-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Cuando flex-basis fue usada en un contenedor de tabla, un objeto StyleGenericFlexBasis podría haberse convertido incorrectamente en el tipo equivocado. Esto resultó en uso de la memoria previamente liberada de la pila, una corrupción de la memoria y un bloqueo potencialmente explotable. Esta vulnerabilidad afecta a Firefox versiones anteriores a 84, Thunderbird versiones anteriores a 78,6 y Firefox ESR versiones anteriores a 78,6

The Mozilla Foundation Security Advisory describes this flaw as:

When `flex-basis` was used on a table wrapper, a `StyleGenericFlexBasis` object could have been incorrectly cast to the wrong type. This resulted in a heap user-after-free, memory corruption, and a potentially exploitable crash.

*Credits: N/A

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

2020-10-12 CVE Reserved
2020-12-16 CVE Published
2023-09-23 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-416: Use After Free
CWE-787: Out-of-bounds Write

CAPEC

References (5)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://www.mozilla.org/security/advisories/mfsa2020-54	2021-01-12
https://www.mozilla.org/security/advisories/mfsa2020-55	2021-01-12
https://www.mozilla.org/security/advisories/mfsa2020-56	2021-01-12
https://access.redhat.com/security/cve/CVE-2020-26974	2020-12-21
https://bugzilla.redhat.com/show_bug.cgi?id=1908024	2020-12-21

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"				< 84.0 Search vendor "Mozilla" for product "Firefox" and version " < 84.0"		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				< 78.6.0 Search vendor "Mozilla" for product "Firefox Esr" and version " < 78.6.0"		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				< 78.6.0 Search vendor "Mozilla" for product "Thunderbird" and version " < 78.6.0"		-		Affected