CVE Feed

    Dashboard / CVE / CVE-2020-6819

    CVE-2020-6819

    Under certain conditions, when running the nsDocShell destructor, 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.

    Published:Apr 3, 2020
    Last Modified:Nov 4, 2025
    EPS:Apr 24, 2020
    EPSS Score:0.00475
    CVSS Score:8.1

    CISA Notification

    Description

    Under certain conditions, when running the nsDocShell destructor, 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.

    Required Action:

    Apply updates per vendor instructions.

    Notes:

    No extra notes provided.

    Due Date
    May 3, 2022
    1592 days ago
    Alert Date
    Nov 3, 2021
    1773 days ago

    Affected Products

    Vendor
    Mozilla
    Product
    Firefox
    Vendor
    Mozilla
    Product
    Thunderbird
    Vendor
    Redhat
    Product
    Enterprise Linux
    Vendor
    Redhat
    Product
    Rhel E4s

    Exploits

    https://bugzilla.mozilla.org/show_bug.cgi?id=1620818https://bugzilla.mozilla.org/show_bug.cgi?id=1620818

    Related CVEs

    CVE-2026-84144 (CVSS 7.5) — Internally found bugs present in Thunderbird 154 and Thunderbird ESR 153.1. Some of these bugs showed evidence…
    CVE-2026-84143 (CVSS 9.8) — Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of th…
    CVE-2026-84142 (CVSS 9.8) — Internally found bugs present in Thunderbird 154. Some of these bugs showed evidence of memory corruption or a…
    CVE-2026-84141 (CVSS 9.8) — Integer overflow in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 155, Firefox ESR…
    CVE-2026-84140 (CVSS 9.8) — Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ES…
    CVE-2026-84139 (CVSS 6.1) — Clickjacking issue in the DOM: Events component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.…
    CVE-2026-84138 (CVSS 6.5) — Denial-of-service in the PDF Viewer component. This vulnerability was fixed in Firefox 155 and Thunderbird 155…
    CVE-2026-84137 (CVSS 4.3) — Spoofing issue in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 155, Firefox ESR 153…
    CVE-2026-84136 (CVSS 6.1) — Other issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, …
    CVE-2026-84135 (CVSS 9.8) — Other issue in Firefox Focus for Android. This vulnerability was fixed in Firefox 155.…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High