Is CVE-2020-6819 actively exploited?

Yes. CVE-2020-6819 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2020-6819 be exploited remotely?

The attack vector of CVE-2020-6819 has not been classified yet.

What is the CVSS score of CVE-2020-6819?

CVE-2020-6819 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2020-6819

HIGHCISA KEVIN THE WILD

CVE-2020-6819

Published: November 3, 2021

EPSS:0.33%probability of exploitation in 30 daysPercentile:55.4th

Official Description

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

NVD Source

CISA KEV Advisory

Mozilla Firefox And Thunderbird Use-After-Free Vulnerability

Added to KEV: 2021-11-03Federal patch deadline: 2022-05-03

Required Action (CISA)

Apply updates per vendor instructions.

Risk Analysis

Mozilla Firefox and Thunderbird are affected by a race condition in the nsDocShell destructor, leading to a use-after-free vulnerability with unspecified impacts. This is a high-severity issue, and its inclusion in CISA's KEV catalog confirms active exploitation, making it an urgent concern despite a low EPSS score of 0.00329.

This vulnerability has been actively exploited in the wild, as confirmed by its presence in CISA's KEV catalog.

Recommended Action

Users of Mozilla Firefox and Thunderbird should update their applications to the latest versions to address this race condition and use-after-free vulnerability.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2020-6819 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2020-6819 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.