CVE-2020-6820

high

Description

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.

From the Tenable Blog

CVE-2020-6819, CVE-2020-6820: Critical Mozilla Firefox Zero-Day Vulnerabilities Exploited in the Wild
CVE-2020-6819, CVE-2020-6820: Critical Mozilla Firefox Zero-Day Vulnerabilities Exploited in the Wild

Published: 2020-04-04

Researchers report multiple zero-day vulnerabilities in Mozilla Firefox and note that other browsers are also affected.

References

Details

Source: Mitre, NVD

Published: 2020-04-24

Updated: 2025-03-21

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 6.8

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 8.1

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.03693