UBUNTU-CVE-2021-43535

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    UBUNTU-CVE-2021-43535

    Published: 8 Dec 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-43535
    Aliases:
    USN-5248-1

    Summary:

    Details: A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.3, and Firefox ESR < 91.3.

    References: https://ubuntu.com/security/CVE-2021-43535, https://www.mozilla.org/security/advisories/mfsa2021-50/, https://www.mozilla.org/security/advisories/mfsa2021-43/, https://www.mozilla.org/security/advisories/mfsa2021-49/, https://bugzilla.mozilla.org/show_bug.cgi?id=1667102, https://ubuntu.com/security/notices/USN-5248-1, https://www.cve.org/CVERecord?id=CVE-2021-43535

    Affected packages

    Package

    Name: thunderbird

    Purl: pkg:deb/ubuntu/thunderbird@1:91.5.0+build1-0ubuntu0.18.04.1?arch=source&distro=bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1:91.5.0+build1-0ubuntu0.18.04.1

    Affected versions

    1:52.4.0+build1-0ubuntu2

    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-2021-43535 | CVE-DB