UBUNTU-CVE-2021-43538

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    UBUNTU-CVE-2021-43538

    Published: 8 Dec 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-43538

    Summary:

    Details: By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for spoofing attacks. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

    References: https://ubuntu.com/security/CVE-2021-43538, https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/#CVE-2021-43538, https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/#CVE-2021-43538, https://www.mozilla.org/en-US/security/advisories/mfsa2021-54/#CVE-2021-43538, https://ubuntu.com/security/notices/USN-5186-1, https://ubuntu.com/security/notices/USN-5246-1, https://ubuntu.com/security/notices/USN-5248-1, https://www.cve.org/CVERecord?id=CVE-2021-43538

    Affected packages

    Package

    Name: firefox

    Purl: pkg:deb/ubuntu/[email protected]+build1-0ubuntu0.18.04.1?arch=source&distro=bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -95.0+build1-0ubuntu0.18.04.1

    Affected versions

    56.0+build6-0ubuntu1

    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
    UBUNTU-CVE-2021-43538 | CVE-DB