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CVE-2020-6819: Mozilla Firefox And Thunderbird Use-After-Free Vulnerability
Mozilla Firefox and Thunderbird · in CISA KEV since 2021-11-03
2021-11-03added to KEV
2022-05-03federal remediation due date
3.04%EPSS exploit probability (30 days) 86.9th percentile
8.1 HIGHCVSS 3.1
Unknownknown ransomware use
558days from NVD publication to KEV
What it is
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.
Required action (CISA)
Apply updates per vendor instructions.
| CWE | CWE-362;CWE-416 |
|---|---|
| CVSS vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD published | 2020-04-24 (Analyzed) |
Original records: NVD · CISA KEV · JSON: /api/cve/CVE-2020-6819.json · all KEV CVEs
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Get the full file: Exploited Vulnerabilities Brief – September 2026 ($29): this month's KEV additions ranked by EPSS, ransomware use and due date, ready to hand to a patch team. Checkout by Polar.